Day 1329

Tuesday.

1710.10264
Probing the relic neutrinos properties with CMB, HST and galaxy clusters
Nunes, Bonilla

Investigate the observational constraints on the CNB (cosmic neutrino background) given by the extended LCDM scenario LCDM + N_eff + m_nu + c_eff^2 + c_vis^2 + xi_nu using the latest observational data from Planck CMB (temperature power spectrum, low-polarization and lensing reconstruction), BAO, the new recent local value of the Hubble constant from HST and information of the abundance of galaxy clusters (GC).  Study the constraints on the CNB background using CMB + BAO + HST data with and without the GC data.  Find Delta N_eff = 0.614±0.26 at 68% CL when the GC data are added in the analysis.  Do not find significant deviation for sound speed in the CNB rest frame.  Also analyze the particular case LCDM + Neff + m_nu + xi+nu with the observational data.  Within this scenario, find Delta N_eff=0.60±0.28 at 68%CL.  In both the scenarios, no mean deviations are found for the degeneracy parameter.


1710.10943
Photometric characterization of the Dark Energy Camera
Bernstein, et al

Characterize the variation in photometric response of the DECam across its 520 Mpix science array during 4 yrs of operation.  This variations are measured using high S/N aperture photometry of >1e7 stellar images in thousands of exposures of a few selected fields, with the telescope dithered to move the sources around the array.  A calibration procedure based on these results brings the RMS variation in aperture magnitudes of bright stars on cloudless nights down to 2-3 mmag, with <1 mmag of correlated photometric errors for stars separated by >=20".  On cloudless nights, any departures of the exposure zero points from a secant airmass low exceeding >1 mmag are plausibly attributable to spatial/temporal variations in aperture corrections.  These variations can be inferred and corrected by measuring the fraction of stellar light in an annulus between 6" and 8" in diameter.  Key elements of this calibration include: correction of amplifier nonlinearities; distinguishing pixel-area variations and stray light from quantum-efficiency variations in the flat fields; field-dependent color corrections; and the use of an aperture-correction proxy.   The DECam response pattern across the 2-degree field drifts over months by up to ±7 mmag, in a nearly-wavelength-independent low-order pattern.  Find no fundamental barrier to pushing global photometric calibrations toward mmag accuracy.


1710.10958
Comparing simulations and test data of a radiation damaged charge-couple device for the Euclid mission
Skottfelt, et al

The VIS instrument on board the Euclid mission is a WL experiment that depends on very precise shape measurements of distant galaxies obtained by a large CCD array.  Due to the harsh radiative environment outside the Earth's atmosphere, it is anticipated that the CCDs over the mission lifetime will be degraded to an extent that these measurements will only be possible through the correction of radiation damage effects.  Create a MC model that simulates the physical processes taking place when transferring signal through a radiation-damaged CCD.  The software is based on Shockley-Read-Hall theory, and is made to mimic the physical properties in the CCD as closely as possible.  The code runs on a single electrode level and takes 3D trap position, potential structure of the pixel, and multi-level clocking into account.  A key element of the model is that it also takes device specific simulations of electron density as a direct input, thereby avoiding to make any analytical assumptions about the size and density of the charge cloud.  This paper illustrates how test data and simulated data can be compared in order to further the understanding of the positions and properties of the individual radiation-induced traps.


1710.011100
The Next Generation Transit Survey (NGTS)
Wheatley, et al

NGTS: a ground-based project searching for transiting exoplanets orbiting bright stars.  Higher photometric precision, and hence find smaller planets than have previously been detected from the ground.  Also operates in red light, maximizing sensitivity to late K and early M dwarf stars.  Survey specs: photometric precision of 0.1% in red light over an instantaneous FoV of 100 sq. degs; enables detection of Neptune-sized exoplanets around Sun-like stars and super-Earths around M dwarfs.  The survey is carried out with a purpose-built facility at Cerro Paranal, Chile, which is the premier site of ESO.  An array of twelve 20cm f/2.8 telescopes fitted with back-illuminated deep-depletion CCD cameras are used to survey fields intensively at intermediate Galactic latitudes.  The instrument is also ideally suited to ground-based photometric follow-up of exoplanet candidates from space telescopes such as TESS, Gaia and PLATO. Present observations that combine precise auto guiding and the superb observing conditions at Paranal to provide routine photometric precision of 0.1% in 1 hr for stars with I-band magnitudes brighter than 13.  Describe the instrument and data analysis methods as well as the status of the survey, which achieved first light in 2015 and began full survey operations in 2016.  NGTS data will be made publicly available through the ESO archive.

Day 1328

Monday.

1710.09839
Detecting black hole binaries by Gaia
Yamaguchi, et al

The prospect of detecting black hole binaries from the orbital motion of the companion stars: ~300-6000 BH binaries during its 5 years of operation, taking into account the IMF, mass transfer, common envelope phase, interstellar absorption and identifiability of BHs.  The shape of distribution function of the BH mass is affected most severely by the relation between the zero-age main sequence (ZAMS) stellar mass and the BH mass in parameters adopted in this paper, which implies that BHs detected with Gaia enables constraints on the mass relation.


1710.09818
Following the cosmic evolution of pristine gas II: the search for Pop III-bright galaxies
Sarmento, et al

Direct observational searches for Pop III stars at high-z are faced with the question of how to select the most promising targets for spectroscopic followup.  To help answer this, use a large-scale cosmological simulation, augmented with a new sub grid model that tracks the fraction of pristine gas, to follow the evolution of high-z galaxies and the Pop III stars they contain.  Generate rest-frame UV luminosity functions for the galaxies and find that they are consistent with current z>=7 observations.  Throughout the range 7<=z<=16 identify "Pop III-bright" galaxies as those with at least 75% of their flux coming from Pop III stars.  While less than 5% of galaxies brighter than m_UV,AB=31.4 mag are Pop III-bright between 7<=z<=8, roughly a 1/3 of such galaxies are Pop III-bright at z=9, right before reionization occurs in the simulation.  Moving to z=10, m_UV,B=31.4 mag corresponds to more luminous galaxies and the Pop III-bright fraction falls off to 15%.  Finally at the highest redshifts, a large fraction of all galaxies are Pop III-bright regardless of magnitude.  While m_UV,AB=31.4 mag galaxies are likely not detectable during this epoch, find 90% of galaxies at z=16 are Pop III-bright with m_UV,AB <=33 mag, a lensed magnitude limit within reach of the JWST.  Thus predict that the best z to search for luminous Pop III-bright galaxies is just before reionization, while lensing surveys for fainter galaxies should push to the highest z possible.


1710.09881
The median density of the Universe
Stücker, Busch, White

Despite the fact that the mean matter density of the universe has been measured to an accuracy of a few percent within the standard LCDM paradigm, its median density is not known even to order of magnitude.  Typical points lie in low-density regions and are not part of a collapsed structure of any scale.  Locally, the dark matter distribution is then simply a stretched version of that in the universe.  In this single-stream regime, the distribution of unsmoothed density is sensitive to the initial power spectrum on all scales, in particular on very small scales, and hence to the nature of dark matter.  It cannot be estimated reliably using conventional cosmological simulations because of the enormous dynamic range involved, but a suitable excursion set procedure can be used instead.  For the Planck cosmological parameters, a 100 GeV WIMP, corresponding to a free-streaming mass ~1e-6 Msun, results in a median density of ~4e-3 in units of the mean density, whereas a 10 ueV axion with free-streaming mass ~1e-12 Msun gives ~3e-3, and WDM with a (thermal relic) mass of 1 keV gives ~8e-2.  In CDM (but not in WDM) universes, single-stream regions are predicted to be topologically isolated by the excursion set formalism.  A test by direct N-body simulations seems to confirm this prediction, although it is still subject to finite size and resolution effects.  Unfortunately, it is unlikely that any of these properties is observable and so suitable for constraining the properties of DM.  


1710.09893
Supernova and prompt gravitational-wave precursors to LIGO gravitational-wave sources and short-GRBs
Michael, Perets

BHs and binary NS mergers had been recently detected through GW emission, with the latter followed by post-merger EM counterparts, appearing seconds up to weeks after the mergers.  While post-merger EM counterparts had been anticipated theoretical, very little EM precursor to GW-sources had been proposed, and non observed yet.  Here show that a fraction of a few times 1e-4 to 1e-1 of LIGO GW-sources and sGRBs could be predicted by SNe-explosions years to decades before the merger.  Each of the BH/NS-progenitors in GW-sources are through to form following a SN, likely accompanied by a natal velocity-kick to the newly born compact object.  The evolution and natal-kicks determine the orbits of surviving binaries, and hence the delay-time between the birth of the compact-binary and its final merger through GW_emission.  Use data from binary evolution population-synthesis models to show that the delay-time distribution has a non-negligible tail of ultra-short delay-times between 1- 100 yrs, thereby giving rise to potentially observable SNe precursors to GW-sources.  Moreover, future LISA/DECIGO GW space-detectors will enable the detection of GW-inspirals in the pre-mergers stage weeks to decades before the final merger.  These ultra-short delay-time sources could therefore produce a unique type of promptly appearing LOSA/DECIGO-GW-sources accompanies by coincident SNe.  The archival (and/or direct) detection of precursor (coincident) SNe with GW and/or sGRBs will provide unprecedented characterization of the merging-binaries, and their prior evolution through SNe and natal kicks, otherwise inaccessible through other means.


1710.09900
A spectroscopic survey of the fields of 28 strong gravitational lenses: implications for $H_0$
Wilson, Zabludoff, Keeton, et al

SL provides an independent measurement of H0.  One remaining systematic is a bias from the additional mass due to a galaxy group at the lens redshift or along the sightline.  Quantify this bias for more than 20 SL that have well-sampled sightline mass distributions, focusing on the convergence kappa and shear gamma.  In 23% of these fields, a lens group contributes a >=1% convergence bias; in 57%, there is a similarly significant LoS group.  For the 9 time delay lens systems, H0 is overestimated by 11+3-2% on average when groups are ignored.  In 67% of fields with total kappa >= 0.01, LoS groups contribute >~2x more convergence than do lens groups, indicating that the lens group is not the only important mass.  Lens environment affects the ratio of 4 (quad) to two (double) image systems; all seven quads have lens groups while only 3 of 10 doubles do, and the highest convergences due to lens groups are in quads.  Calibrate the gamma-kappa relation: log(kappa_tot) =(1.94±0.34) log(gamma_tot) + (1.31±0.49) with a rms scatter of 0.34 dex.  Shear, which, unlike convergence, can be measured directly from lensed images, can be a poor predictor of kappa; for 19% of the fields, kappa is >~2 gamma.  Thus, accurate cosmology using strong gravitational lenses requires precise measurement and correction for all significant structures in each lens field.


1710.09902
A comparison of the excess mass around CFHTLenS galaxy-pairs to predictions from a semi-analytic model using galaxy-galaxy-galaxy lensing
Simon, Saghiha, Hilbert, Schneider, Boever

G3L lensing is a probe of the matter environment of average galaxy pairs, which is a strong test for galaxy models.  Using G3L, map out the distribution of correlated excess-mass around galaxy pairs in the CFHTLenS in a reanalysis of the data.  Compare the maps to predictions by a recent SAM which is implanted on the Millennium Simulation.  The target galaxies span a range of stellar masses between 1e9-11 Msun, and have z <~0.6 in two z bins; the projected separation between galaxies pairs is chosen between ~170-300 kpc/h in two separation bins.  Compared to an earlier G3L study with CFHTLenS galaxies, make more efficient use of the data.  In addition, verify the accuracy of the refined stacking technique for the map construction with simulated data and provide a detailed description of the methodology.  For a better interpretation of the maps, discuss the impact of chance pairs, i.e., galaxy pairs that appear close to each other in projection only, and introduce an alternative correlation map that is less affected by projection effects but has a lower S/N.  For all maps, obtain significant measurements of the excess-mass distribution for all galaxy samples and an overall good agreement with the SAM predictions.  There is, however, tentative evidence for a bulge-like feature in the distribution of excess mass that is not predicted by the SAM and similar models.  Although there is no strong indications for systematic errors in the maps, this feature may be related to a residual B-mode pattern visible in the average of all maps.  Alternatively, misaligned galaxy pairs inside matter haloes or lensing by a misaligned distribution of the intra-cluster gas might also cause a bulge.


1710.09908
A spectroscopic survey of the fields of 28 strong gravitational lenses: the Group Catalog
Wilson, et al

Observational companion paper to 1710.09900.  Find 210 groups with at least 5 member galaxies; the median number of members is 8.

Day 1327

Friday.

1710.09465
Parameter constraints from cross-correlation of CMB lensing with galaxy clustering
Schmittfull, Seljak

The lensing convergence measurable with future CMB surveys like CMB-S4 will be highly correlated with the clustering observed by deep photometric LSS surveys such as the LSST, with cross-correlation coefficient as high as 95%.  This will enable use of sample variance cancellation techniques to determine cosmological parameters, and use of cross-correlation measurements to break parameter degeneracies.  Assuming large sky overlap between CMB-S4 and LSST, show that a joint analysis of CMB-S4 lensing and LSST clustering can yield very tight constraints on the matter amplitude sigma8(z), halo bias, and f_NL, competitive with the best stage IV experiment predictions, but using complementary methods, which may carry different and possibly lower systematics.  Having no sky overlap between experiments degrades the precision of sigma8(z) by a factor of 20, and that of f_NL by a factor of 1.5 to 2.  Without CMB lensing, the precision always degrades by an order of magnitude or more, showing that a joint analysis is critical.  The results also suggest that CMB lensing in combination with LSS photomtetric surveys is a competitive probe of the evolution of structure in the range z~1-7, probing a regime that is not well tested observationally.  Explore predictions against other surveys and experiment configurations, finding that wide patches with maximal sky overlap between CMB and LSS surveys are most powerful for sigma8(z) and f_NL.


1710.09573
Time resolved 2 million year old supernova activity discovered in Earth's microfossil record
Ludwig, et al

Massive stars, which terminate their evolution as core collapse supernovae, are theoretically predicted to eject more than 1e-5 Msun of the radioisotope 60Fe.  If such an event occurs sufficiently close to the solar system, traces of the supernova debris could be deposited on Earth.  Report a time resolved 60Fe signal residing, at least partially, in a biogenic reservoir.  Using accelerator mass spectrometry, this signal was found through the direct detection of live 60Fe atoms contained within secondary iron oxides, among which are magnetofossils, the fossilized chains of magnitite crystals produced by magnetotactic bacteria.  The magnetofossiles were chemically extracted from two Pasific Ocean sediment drill cores.  The results show that the 60Fe signal onset occurs around 2.6 Ma to 2.8 Ma, near the lower Pleistocene boundary, terminates around 1.7 Ma, and peaks at about 2.2 Ma.

Day 1326

Thursday.

1710.08924
The fast transient sky with Gaia
Wevers, et al

Each time a source passes within the Gaia field of view, it moves over 10 CCDs in 45 s: a light curve with 4.5 s sampling is registered.  Filter out instrumental and data processing artifacts in the light curve.  Statistical methods to identify sources that show transient brightness variations on ~2hrs timescales + ability to detect transient brightness variations down to 0.3 mag on timescales from 15 seconds to several hours.  In ~23.5 deg^2 on the sky, find 4 strong candidate fast transients.  2 are tentatively classified as M-dwarf star flares; one is probably a flare on a giant star, and one potentially a flare on a solar type star, based on archival data and timescales involved.  This method can be added to the existing Gaia science alerts infrastructure for the near real-time public dissemination of fast transient events.

Day 1325

Wednesday.

1710.08489
Scientific synergy between LSST and Euclid
Rhodes, et al

Euclid and LSST are poised to dramatically change the astronomy landscape early in the next decade.  The combination of high cadence, deep, wide-field optical photometry from LSST with high resolution, wide-field optical photometry and near-IR photometry and spectroscopy from Euclid will be powerful for addressing a wide range of astrophysical questions.  Explore Euclid/LSST synergy, ignoring the political issues associated with data access to focus on the scientific, technical, and financial benefits of coordination.  Focus primarily on DE cosmology, but also discuss galaxy evolution, transient objects, solar system science, and galaxy cluster studies.  Concentrate on synergies that require coordination in cadence or survey overlap, or would benefit from pixel-level co-processing that is beyond the scope of what is currently planned, rather than scientific programs that could be accomplished only at the catalog level without coordination in data processing or survey strategies.  Provide two quantitative examples of scientific synergies: the decrease in photo-z errors (benefitting many science cases) when high resolution Euclid data are used for LSST photo-z determination, and the resulting increase in WL S/N ratio from smaller photo-z errors.  Briefly discuss other areas of coordination, including high performance computing resources and calibration data.  Finally, address concerns about the loss of independence and potential cross-checks between the two missions and potential consequences of not collaborating.

Day 1324

Tuesday.  Wednesday.

1710.08150
MultiDark-Galaxies: data release and first results
Knebe et al

Planck Cosmology MultiDark sims, applying SAMs GALACTICUS, SAG, and SAGE. volume of 1 (Gpc/h)^3 and mass resolution of 1.5e9 Msun/h.  Compare models with observation for: stellar mass function, SFR, cold gas fractions, and metallicities.  Selected galaxy subsamples of catalogues by number densities in stellar mass, cold gas mass, and SFR in order to study the clustering statistics of galaxies.  Show that despite different treatment of orphan galaxies (galaxies that lost their DM host halo due to the finite mass resolution of the N-body sim or tidal stripping) the clustering signal is comparable, and reproduces the observations in all 3 models - in particular when selecting samples based upon stellar mass.  The catalogues provide a powerful tool to study galaxy formation within a volume comparable to those probed by on-going and future photometric and z surveys.  All model data consisting of a range of galaxy properties - including broad-band SDSS magnitudes - are publicly available. 

Day 1323

Wednesday, Thursday, Friday.  Monday.

1710.05931
Welcome to the multi-messenger era!  Lessons from a neutron star merger and the landscape ahead
Metzger

The discovery by Advanced LIGO/Virgo of gravitational waves from the binary NS merger GW170817, and subsequently by astronomers of transient counterparts across the EM spectrum, has initiated the era of multi-messenger astronomy.  Given the slew of papers appearing on this event, thought it useful to summarize the EM discoveries in the context of theoretical models and present the views on the major take-away lessons from this watershed event.  The weak GRB discovered in close time coincidence with GW170817, and potential evidence for a more powerful off-axis relativistic jet (initially beamed away from our line of sight) from the delayed rise of a non-thermal X-ray and radio orphan afterglow, provides the most compelling evidence yet that cosmological sGRBs originate from binary NS mergers.  The luminosity and colors of the early optical emission discovered within a day of the merger agrees strikingly well with original predictions (Metzger+2010) for "kilonova" emission powered by the radioactive decay of r-process nuclei, the NS merger origin of which was initially proposed by Lattimer+Schramm 1974.  The transition of the spectral energy distribution to NIR wavelengths on timescales of days matches predictions by Barnes+Kasen 2013 and Tanaka+Hotokezaka 2013 if a portion of the ejecta contains heavy r-process nuclei with higher opacities.  The "blue" and "red" ejecta components may possess distinct origins (e.g. dynamical ejecta versus accretion disk outflows), with key implications for the merger physics and the properties of neutron stars.  Outline the diversity in the EM emission expected from additional mergers--observed with different binary masses and viewing angles--discovered once LIGO/Virgo reach design sensitivity and NS mergers are discovered as frequently as once per week.


1710.05951
An independent determination of the local Hubble constant
Fernández-Arenas, et al

Obtain H0 from the relationship between the integrated H_beta line luminosity and the velocity dispersion of the ionized gas of HII galaxies and giant HII regions, a standard candle that presently can be used up to z~4.  Hubble constant measurements from the combination of the slope of the relation obtained from z<0.2 HII galaxies with the zero point determined from giant HII regions belonging to an 'anchor sample of galaxies for which accurate z-independent distance moduli are available.  Data for 36 giant HII regions in 13 galaxies; this data is the first 4 years of obseration of the primary sample of 130 giant HII regions in 73 galaxies with Cepheid determined distances.  The best estimate of the Hubble parameter is 71.0±2.8(random)±2.1(systematic) km/s/Mpc.  This result is the product of an independent approach and, although at present less precise than the latest SNIa results, it is amenable to substantial improvement.


1710.06168
GW170817 Falsifies dark matter emulators
Boran, et al

Simultaneous detection of GW and EM signals from GW170817 rules out a class of modified gravity theories which dispense with the need for DM.  This simultaneous observation also provides the first ever test of Einstein's Weak Equivalence Principle between gravitons and photons.  Calculate the Shapiro time delay due to the gravitational potential of the total DM distribution along the LoS to be about 1000 days.  Using this estimate from the Shapiro delay and from the time difference of 1.7 seconds between the GW signal and gamma-rays, constrain violations of WEP using the pamaeterized post-Newtonian (PPN) parameter gamma, and is given by gamma_GW - gamma_EM < 3.9e-8.


1710.06427
Constraints from the time lag between gravitational waves and gamma rays: implications of GW170817 and GRB170817A
Shoemaker, Murase

The EM detection of GW170817, including the sGRB within Delta t~2s after the GW arrival, can be used to test various aspects of sources physics and GW propagation.  Using GW170817 as the first GW-EM example, show that this event provides a stringent direct test that GWs travel at the speed of light.  The gravitational potential of the Milky Way provides a potential sources of Shapiro time delay difference between the arrival of photons and GWs, and demonstrate that the nearly coincident detection of the GW and EM signals can yield strong limits on anomalous gravitational time delay, through updating the previous limits taking in to account details of MW's gravitational potential.  Finally, also obtain an intriguing limit on the size of the prompt emission region GRB170817A, and discuss implications for the emission mechanism of sGMBs.


1710.06426
Improved constraints on H0 from a combined analysis of gravitational-wave and electromagnetic emission from GW170817
Guidorzi, et al

H0=74.0±(13.7/5.3) km/s/Mpc, "note that this is in modestly better agreement with the local distance latter than the Planck CMB, though a significant such discrimination will require ~50 such events."


1710.06424
Prospects of the local Hubble parameter measurement using gravitational waves from double neutron stars
Seto, Kyutoku

For a good fraction >~50% of the double NS events within 200 Mpc, could identify their host galaxies.  Depending on the DNS merger rate, could measure the local Hubble parameters H_L at the level (Delta H_L/H_L) ~ 0.042 (1 sigma CL), after the 3rd observation run (O3).


1710.06431
Weak lensing magnification of SpARCS galaxy clusters
Turodrica, Hildebrand, et al

Measuring and calibrating relations between cluster observables is critical for resource-limited studies.  The mass-richness relation of clusters offers an observationally inexpensive way of estimating masses.  Its calibration is essential for cluster and cosmological studies, especially for high-z clusters.  WL magnification is a promising and complementary method to shear studies, that can be applied at higher z.  Employed the WL magnification method to calibrate the mass-richness relation up to z~1.4.  Used SpARCS galaxy cluster candidates (0.2<z<1.4) and optical data from CFHT to test whether magnification can be effetively used to constrain the mass of high-z clusters.  LBGs (Lyman-break galaxies) selected using the u-band dropout technique and their colors were used as a BG sample of sources.  LBG positions were cross-correlated with the centers of the sample of SpARCS clusters to estimate the magnification signal measured for cluster sub-samples, binned in both z and richness.  Detected a WL magnification signal for all bins at a detection significance of 2.6-5.5 sigma.  In particular, the significance of the measurement for clusters with z>1.0 is 4.1 sigma; for the entire cluster sample, obtained an average of M_200 of 1.28(+0.23-0.21)e14 Msun.  The measurements demonstrated the feasibility of using WL magnification as a viable tool for determining the average halo masses for samples of high-z galaxy clusters.  The results also established the success of using galaxy over-densities to select massive clusters at z>1.  Additional studies are necessary for further modeling of the various systematic effects discussed.


1710.06739
Gaia data relate 1 cross-match with external catalogues - algorithm and results
Marrese, et al

Combination of high accuracy archive with other archives useful -- the interoperation of archives is based on cross-matching; data retrieval should work not only across data archives but also across wavelength domains.  Describe the cross-match algorithm used to pre-computed the match of Gaia DR1 catalogues with a selected list of large optical and IR surveys publicly available.  The overall principles of the adopted cross-match algorithm are outlined.  Details are given on the developed algorithm, including the methods to account for position errors, proper motions and environment, to define the neighbors and to define the future of merit used to select the most probable counterpart.  Statistics on the results are also given.  The results of the cross-match are part of the official Gaia DR1 release.


1710.06808
The splash back feature around DES galaxy clusters: galaxy density and weak lensing profiles
Chang, et al

Splashback refers to the process of matter than is accreting onto a DM halo reaching its first orbital apocenter and turning around in its orbit.  The cluster-centric radius at which this process occurs, r_sp, defines a halo boundary that is connected to the dynamics of the cluster, in contrast with other common halo boundary definitions such as R_200.  A rapid decline in the matter density profile of the halo is expected near r_sp.  Measure the galaxy number density and WL mass profiles around RedMapper galaxy clusters in the DES data.  For a cluster sample with mean mass 2.5e14 Msun, find strong evidence of a splashback-like steepening of the galaxy density profile and measure r_sp=1.16±0.08 Mpc/h, consistent with earlier SDSS measurements of More+2016 and Baxter+2017.  Moreover, the WL measurement demonstrates for the first time the existence of splashback-like steepening of the matter profile of galaxy clusters.  Measure r_sp=1.28±0.18 Mpc/h from the WL data, in good agreement with the galaxy density measurements.  Applying the analysis to different cluster and galaxy samples, find that consistent with LCDM simulations, r_sp scales with R_200m and does not evolve with redshift over the range 0.3<z<0.6.  Also find that potential systematic effects associated wit the RedMapper algorithm may impact the location of r_sp, in particular the choice of scale used to estimate cluster richness.  Discuss progress needed to understand the systematic uncertainties and fully exploit forthcoming data from DES and future surveys, emphasizing the importance of more realistic mock catalogs and independent cluster samples.

Day 1322

Tuesday.  

1710.05045
Density split statistics: cosmological constraints from counts and lensing in cells in DES Y1 and SDSS
Gruen, et al

Derive cosmological constraints from the PDF of evolved LS matter density fluctuations.  This is done by splitting lines of sight by density based on their count of tracer galaxies, and by measuring both gravitational shear around and counts-in-cells in overdense and underdense lines of sight, in DES Y1 and SDSS data.  The analysis uses a perturbation theory model (see companion paper Friedrich+) and is validated using N-body simulation realizations and log-normal mocks.  It allows constraints on cosmology, bias and stochasticity of galaxies wrt matter density and, in addition, the skewness of the matter density field.  From a Bayesian model comparison, find that the data weakly prefer a connection of galaxies and matter that is stochastic beyond Poisson fluctuations on <= 20 arcmin angular smoothing scale.  The two stochasticity models fit yield DES constrains on the matter density Omega_m=0.26+0.04-0.03 and Omega_m=0.28+0.05-0.04 that are consistent with each other.  These values also agree with the DES analysis of galaxy and shear 2pt functions (3x2 pt) that only uses second moments of the PDF.  Constraints on sigma8 are model dependent (sigma8=0.97+0.07-0.06 and 0.80+0.06-0.07 for the 2 stochasticity models), but consistent with each other and with the 3x2pt results if stochasticity is at the low end of the posterior range.  As an additional test of gravity, counts and lensing in cells allow to compare the skewness S3 of the matter density PDF to its LCDM prediction.  Find no evidence of excess skewness in any model or data set, with better than 25% relative precision in the skewness estimate from DES alone.


1710.05162
Density spilt statistics: joint model of counts and lensing in cells
Friedrich, Gruen, et al

Present density spit statistics, a framework that studies lensing and counts-in-cells as a function of FG galaxy density, thereby providing a LS measurement of both 2pt and 3pt statistics.  The method extends the earlier work on trough lensing and is summarized as follows: given a FG (low z) population of galaxies, divide the sky into subareas of equal size but distinct galaxy density.  Then measure lensing around uniformly spaced points separately in each of these subareas, as well as counts-in-cells statistics (CiC).  The lensing signals trace the matter density contrast around regions of fixed galaxy density.  Through the CiC measurements this can be related to the density profile around regions of fixed matter density.  Together, these measurements constitute a powerful probe of cosmology, the skewness of the density field and the connection of galaxies and matter.  In this paper, show how to model both the density split lensing signal and CiC from basic ingredients: a non-linear power spectrum, clustering hierarchy coefficients from perturbation theory and a parametric model for galaxy bias and shot-noise.  Using N-body simulations, demonstrate that this model is sufficiently accurate for a cosmological analysis on year 1 data from the DES.


1710.05434
Electromagnetic evidence that SSS17a is the result of a binary neutron star merger
Kilpatrick, et al

11 hrs after the detection of GW source GW170817 by the LIGO and Virgo interferometers, an associated optical transient SSS17a was discovered in the galaxy NGC 4993.  While the gravitational wave data indicate GW170817 is consistent with the merger of two compact objects, the electromagnetic observations provide independent constraints of the nature of that system.  Here, synthesize all optical and NIR photometry and spectroscopy of SSS17a collected by the One-Meter Two-Hemisphere collaboration. Find that SSS17a is unlike other known transients.  The source is best described by theoretical models of a kilo nova consisting of radioactive elements produced by rapid neutron capture (the r-process).  Find that SSS17a was the result of a binary neutron star merger, reinforcing the gravitational wave result.


1710.05833
Multi-messenger observations of a binary neutron star merger
LIGO, Virgo, Fermi GBM, INTEGRAL, IceCube, AstroSat, IPN, Insight-Hxmt, ANTARES, Swift, AGILE, 1M2H, DEC GW-EM, DES, DLT40, GRAWITA, Fermi-LAT, ATCA, +50 others

On 2017 August 17 a binary NS coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors.  The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7s with respect to the merger time.  From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40±8 Mpc and with component masses consistent with NS.  The component masses were later measured to be in the range 0.86 to 2.26 Msun.  An extensive observing campaign was launched across the EM spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mac) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1m Swope telescope.  The optical transient was independently detected by multiple teams within an hour.  Subsequent observations targeted the object and its environment.  Early UV observations revealed a blue transient that faded within 48 hrs.  Optical and infrared observations showed a reward evolution over ~10 days.  Following early non-detections, X-ray and radio emission were discovered at the transient's position ~9 and ~16 days, respectively, after the merger.  Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-IR emission.  No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches.


1710.05835
A gravitational-wave standard siren measurement of the Hubble constant
Abbott, + >1300 other authors

Combine the distance to the source inferred purely from the GW signal with the recession velocity inferred from redshifts using EM data.  ...determine the Hubble constant to be 70.0+12.0-8.0 km/s/Mpc (68% CL).  Consistent with existing measurements, while being completely independent of them.



1710.05457
The Electromagnetic counterpart of the binary neutron star merger LIGO/VIRGO GW170817. VI. Radio constraints on a relativistic jet and predictions for late-time emission from the kilonova ejecta
Alexander, et al

...EM counterpart detected in optical 13.7 hrs after merger, and millimeter 2.41 days post merger.  6GHz detection at 19.5 and 39.2 days after the merger, but not in an earlier observation at 2.5 days.  No detection of dm/mm emission at the position of the optical counterpart at frequencies of 10-97.5 Ghz at times ranging from 0.6 to 30 days post merger, ruling out an on-axis sGRB for energies >=1e48 erg.  For fiducial sGRB parameters, the limits require an observer viewer angle of >~20 deg.  The radio and X-ray data can be jointly explained as the afterglow emission from an sGRB with a jet energy of 1e49-50 erg that exploded in a uniform density environment with n~1e-4 to 1e-2 cm^-3, viewed at an angle of ~20-40 degrees from the jet axis.  Using the results of the light curve and spectral modeling, in conjunction with the inference of the circumbinary density, predict the emergence of late-time radio emission from the deceleration of the kilonova ejecta on a timescale of ~5-10 years that will remain detectable for decades with next-generation radio facilities, makingGW170817 a compelling target for long-term radio monitoring.


1710.05438
The electromagnetic counterpart of the binary neutron star merger LIGO/VIRGO GW170817.  VIII. a comparison to cosmological short-duration gamma-ray bursts
Fong, et al

Compare with a sample of 36 sGRBs spanning 0.12<z<2.6 discovered over 2004-2017.  Find that the counterpart to GW170817 has an isotropic-equivalent luminosity that is ~3000x less than the median value of on-axis short GRB X-ray afterglows, and >1e4 times less than that for detected sGRB radio afterglows.  The allowed jet energies and particle densities inferred from the radio and X-ray counterparts to GW170817 and on-axis sGRB afterglows are remarkably similar, suggesting that viewing angle effects are the dominant, and perhaps only, difference in their observed radio and X-ray behavior.  From comparison to previous claimed kilonovae following sGRBs, find that the optical and near-IR counterpart to GW170817 is comparatively under-luminous by a factor of 3-5, indicating a range of kilonova luminosities and timescales.  A comparison of the optical limits following sGRBs on <1day timescales also rules out a "blue" kilo nova of comparable optical isotropic-equivalent luminosity in one previous sGRB.  Investigate the host galaxy NGC4993, in the context of sGRB host galaxy stellar population properties.  Find that NGC4993 is superlative in terms of its large luminosity, old stellar population age, and low SFR compared to previous sGRB hosts.  Additional events within Advanced LIGO/VIGO volume will be crucial in delineating the properties of the host galaxies of NS-NS mergers, and connecting them to their cosmological counterparts.

Day 1321

Wednesday.  Thursday.  Friday.  Monday.

1710.03235
Weak lensing for precision cosmology
Mandelbaum

WL, the deflection of light by mass, is one of the best tools to constrain the growth of cosmic structure with time and reveal the nature of DE.  Discuss the sources of systematic uncertainty in WL measurements and their theoretical interpretation, including the current understanding and other options for future improvement.  These include long-standing concerns such as the estimation of coherent shears from galaxy images or redshift distributions of galaxies selected based on photometric z, along with systematic uncertainties that have received less attention to date because they are subdominant contributors to the error budget in current surveys.  Also discuss methods for automated systematics detection using survey data of the 2020s.  The goal of this review is to describe the current state of the field and what must be done so that if WL measurements lead toward surprising conclusions about key questions such as the nature of DE, those conclusion will be credible.  


1710.03251
Halo mass and weak galaxy-galaxy lensing profiles in rescaled cosmological $N$-body simulations
Reneby, Hilbert, Angulo

Investigate 3D density and WL profiles of DM haloes predicted by a cosmology-rescaling algorithm for $N$-body simulations.  Extend the rescaling method of Angulo+White (2010) and Angulo+Hilbert (2015) to improve its performance on intra-halo scales by using models for the concentration-mass-z relation based on excursion set theory.  The method's accuracy is tested with numerical simulations carried out with different cosmological parameters.  Find that predictions for median density profiles are more accurate than ~5%, for haloes with masses of 1e12.0 - 1e14.5 Msun/h for radii 0.05 < r/r_200 < 0.5, and for cosmologies with Omega_m in [0.15, 0.40] and sigma8 in [0.6, 1.0].  For larger radii, 0.5 < r/r200 < 5, the accuracy degrades to ~20% due to inaccurate modeling of the cosmological and z dependence of the splash back radius.  For changes in cosmology allowed by current data, the residuals decrease to ~<2%, up to scales twice the viral radius.  Illustrate the usefulness of the method by estimating the mean halo mass of a mock galaxy group sample.  Find that the algorithm's accuracy is sufficient for current data.  Improvements in the algorithm, particularly in the modeling of baryons, are likely required for interpreting future (DE task force stage IV) experiments.


1710.03747
Measuring the small-scale matter power spectrum with high-resolution CMB lensing
Nguyen, Sehgal, Madhavacheril

Present a method to measure the small-scale matter power spectrum using high-resolution measurements of the gravitational lensing of the CMB.  To determine whether small-scale structure today is suppressed on scales below 10 kpc (corresponding to M<1e9 Msun), one needs to probe CMB-lensing modes out to ell~35,000, requiring a CMB experiment with about 20 arc second resolution or better.  Show that a CMB survey covering 4,000 sq degs of sky, with an instrumental sensitivity of 0.5 uK-arcmin at 18 arc second resolution, could distinguish between cold DM and an alternative, such as 1keV warm DM or 1e-22 eV fuzzy DM with a bout 4-sigma significance.  A survey of the same resolution with 0.1 uK-arcmin noise could distinguish between CDM and these alternatives at better than 20-sigma significance; such high-significance measurements may also allow one to distinguish between a suppression of power due to either baryonic effects or the particle nature of DM, since each impacts the shape of the lensing PS differently.  CMB temperature maps yield higher S/N than polarization maps in this small-scale regime; thus, systematic effects, such as from extragalactic astrophysical foregrounds, need to be carefully considered.  However, these systematic concerns can likely be mitigated with known techniques.  Next-generation CMB lensing may thus provide a robust and powerful method of measuring the small-scale matter power spectrum.


1710.04301
The LAMOST Complete spectroscopic survey of pointing area (LaCoSSPAr) in the southern galactic cap I.  The spectroscopic redshift catalog
Yang, et al

In the southern galactic cap (SGC), limiting magnitude of r=18.1 mag, in two 20 deg^2 fields.  Focusing on completeness and the deficiencies of source selection methods and at the basic performance parameters of LAMOST telescope.  In both fields, >95% of galaxies observed.  Majority of remaining sky background residuals removed from the 1D spectrum.  >10k spectra visually inspected, using combinations of emission/absorption features with sigma_z/(1+z) < 0.001.  1528 redshifts in field A and 1570 z in field B measured.  Results show that it is possible to derive z from low SNR galaxies with the post-processing and visual inspection.  The analysis also indicates that up to 1/4 of the input targets for a typical extra-galactic spectroscopic survey might be unreliable.  The multi-wavelength data analysis shows that the majority of mid IR detected absorption (91.3%) and emission ling galaxies (93.3%) can be well separated by an empirical criterion of W2-W3=2.4.  Meanwhile, a fainter sequence paralleled to the main population of galaxies has been witnessed both in Mr/W2-W3 and M*/W2-W3 diagrams, which could be the population of luminous dwarf galaxies but contaminated by the edge-on/highly inclined galaxies (~30%).


1710.04896
Improving catalog matching by supplementing astrometry with additional photometric information
Wilson, Naylor

Apply to IPHAS-Gaia matches (different dynamical ranges), and IPHAS and 2MASS (approximately equal astrometric precision).  Important to include magnitude information in both cases.  Discuss extending the method to multiple catalogue matches through an interactive matching process.  The method allows for the selection of high-quality matches by providing an overall probability for each pairing, giving the flexibility to choose stars know to be good matches.

Day 1320

Tuesday.

1710.02530
Unique signatures of Population III stars in the global 21-cm signal
Mirocha, et al

Investigate the effects of Pop III stars on the sky-averaged 21-cm background radiation, which traces the collective emission from all sources of UV and X-ray photons before reionization incomplete.  While UV photons from PopIII stars can in principle shift the onset of radiative coupling of the 21-cm transition -- and potentially reionization -- to early times, find that the remnants of PopIII stars are likely to have a more discernible impact on the 21-cm signal than PopIII stars themselves.  The X-rays from such sources preferentially heat the IGM at early times, which elongates the epoch of reheating and results in a more gradual transition from an absorption signal to emission.  This gradual heating gives rise to broad, asymmetric wings in the absorption signal, which stand in contrast to the relatively sharp, symmetric signals that arise in models treating PopII sources only.  A stronger signature of PopIII, in which the position of the absorption minimum becomes inconsistent with PopII-only models, requires extreme SF events that may not be physically plausible, lending further credence to predictions of relatively high frequency absorption troughs, nu_min ~ 100 MHz.  As a result, though the trough location alone may not be enough to indicate the presence of PopIII, the asymmetric wings should arise even if only a few PopIII stars form in each halo before the transition to PopII star formation occurs, provided that the PopIII IMF is sufficiently top-heavy and at least some PopIII stars form in binaries.


1710.03075
The inner mass power spectrum of galaxies using strong gravitational lensing: beyond linear approximation
Chatterjee, Koopmans

In the last decade the detection of individual massive dark matter sub-haloes has been possible using potential correction formalism in SL imaging.  Propose a statistical formalism to relate SL surface brightness anomalies to the lens potential fluctuations arising from DM distribution in the lens galaxy.  Consider these fluctuations as a Gaussian random field in addition to the unperturbed smooth lens model.  This is very similar to WL formalism and show that in this way, can measure the power spectrum of these perturbations to the potential.  Test the method by applying it to simulated mock lenses of different geometries and by performing an MCMC analysis of the theoretical power spectra.  This method can measure density fluctuations in early type galaxies on scales of 1-10 kpc at typical rms-levels of a percent, using a single lens system observed with the HST with typical S/N ratios obtained in a single orbit.

Day 1319

Friday.  Monday.

1710.02517
Dark Energy Survey Year 1 results: cross-correlation redshifts in the DES -- calibration of the weak lensing source redshift distributions
Davis, et al

Present the calibration of the DES Y1 WL source galaxy redshift distributions from clustering measurements.  By cross-correlating the positions of source galaxies with  LRGs selected by the redMaGiC algorithm, measure the z distributions of the source galaxies as placed into different tomographic bins.  These measurements constrain any such shifts to an accuracy of ~0.02 and can be computed even when the clustering measurements do not span the full z range.  The highest-z source bin is not constrained by the clustering measurements because of the minimal z overlap with the redMaGiC galaxies.  Compare the constraints with those obtained from COMOS 30-band survey and find that the 2 very different methods produce consistent constraints.

Day 1318

Thursday.

1710.01303
Cosmic shear with Einstein Rings
Birrer, Referier, Amara

Explore a new technique to measure cosmic shear using Einstein rings as standard shapes.  Einstein rings are formed the a strong lensing system has circular symmetry.  These rings can become elliptical due to WL by foreground structures.  Birrer+(2017) showed that the detailed modeling of Einstein rings can be used to measure external shear to high precision.  In this letter, explore how a collection of Einstein rings can be used as a statistical probe of cosmic shear.  Present a forecast of the cosmic shear information available in Einstein rings for different strong lensing survey configurations.  Find that, assuming that the number density of Einstein rings in the COSMOS survey is representative, future strong lensing surveys should have a cosmological precision comparable to the current ground based WL surveys.  Discuss how this technique is complementary to the standard cosmic shear analyses since it is sensitive to different systematic and can be used for cross-calibration.


1710.01314
The Herschel Space Observatory has revealed a very different galaxyscape from that shown by optical surveys which presents a challenge for galaxy-evolution models.  The Herschel surveys reveal (1) that there was rapid galaxy evolution in the very recent past and (2) that galaxies lie on a single Galaxy Sequence (GS) rather than a star-forming `main sequence' and a separate region of `passive' or `red-and-dead' galaxies.  The form of the GS is now clearer because FIR surveys such as the Herschel ATLAS pick up a population of optically-red SF galaxies that would have been classified as passive using most optical criteria.  The space-density of this population is at least as high as the traditional SF population.  By stacking spectra of H-ATLAS galaxies over the range 0.001<z<0.4, show that the galaxies responsible for the rapid low-z evolution have high stellar masses, high SF rates but, even several billion years in the past, old stellar populations - they are thus likely to be relatively recent ancestors of early-type galaxies in the Universe today.  The form of the GS is inconsistent with rapid quenching models and neither the analytic bathtub model nor the hydrodynamical EAGLE simulation can reproduce the rapid cosmic evolution.  Propose a new gentler model of galaxy evolution that can explain the new Herschel results and other key properties of the galaxy population.

Day 1317

Wednesday.

1710.00885
Weak lensing shear calibration with simulations of the HSC survey
Mandelbaum, et al

Present results from a set of simulations designed to constrain the WL shear calibration for the HSC survey.  These simulations include HSC observing conditions and galaxy images from HST, with fully realistic galaxy morphologies and the impact of nearby galaxies included.  Find that the inclusion of nearby galaxies in the images is critical to reproducing the observed distributions of galaxy sizes and magnitudes, due to the non-negligible fraction of unrecognized blends in ground-based data, even with the excellent typical seeing of the HSC survey (0.58" in the i-band).  Using these simulations, detect and remove the impact of selection biases due to the correlation of weights and the quantities used to define the sample (S/N and apparent size) with the lensing shear.  Quantify and remove galaxy property-dependent multiplicative and additive shear biases that are intrinsic to the shear estimation method, including a ~10% level multiplicative bias due to the impact of nearby galaxies and unrecognized blends.  Finally, check the sensitivity of the shear calibration estimates to other cuts made on the simulated samples, and find that the changes in shear calibration are well within the requirements for HSC WL analysis.  Overall, the simulations suggest that the WL multiplicative biases in the first-year HSC shear catalog are controlled at the 1% level.

Day 1316

Tuesday.

1710.00007
A Bayesian hierarchical approach to galaxy-galaxy lensing
Sonnenfeld, Leauthaud

Present a Bayesian hierarchical inference formalism to study the relation between the properties of dark matter haloes and those of their central galaxies using WL.  Unlike traditional methods, this technique does not resort to stacking the WL signal in bins, and thus allows for a more efficient use of the information content in the data.  The method is particularly useful for constraining scaling relations between 2 or more galaxy properties and DM halo mass, and can also be used to constrain the intrinsic scatter in these scaling relations.  Show that, if observational scatter is not properly accounted for, the traditional stacking method can produce biased results when exploring correlations between multiple galaxy properties and halo mass.  For example, this bias can affect studies of the joint correlation between galaxy mass, halo mass, and galaxy size, or galaxy color.  In contrast, the method here easily and efficiently handles the intrinsic and observational scatter in multiple galaxy properties and halo mass.  Test the method on mocks with varying degrees of complexity.  Find that the mean halo mass and concentration can be recovered, each with a 0.1 dex accuracy, and the intrinsic scatter in halo mass with a 0.05 dex accuracy.  In its current version, the method will be most useful for studying the WL signal around central galaxies in groups and clusters, as well as massive galaxies samples with log(M*)>11, which have low satellite fractions.


1710.00434
Origin of the RNA World: the fate of nucleases in warm little ponds
Pearce, et al

Prior to the origin of simple cellular life, the building blocks of RNA (nucleotides) had to form and polymerize in favorable environments on the early Earth.  At this time, meteorites and interplanetary dust particles delivered organics such as nucleases (the characteristic molecules of nucleotides) to warm little ponds whose wet-dry cycles promoted rapid polymerization.  Build a comprehensive numerical model for the evolution of nucleases in warm little ponds leading to the emergence of the first nucleosides and RNA.  Couple Earth's early evolution with complex prebiotic chemistry in these environments.  Find that RNA polymers must have emerged very quickly after the deposition of meteorites (< a few years).  Their constituent nucleases were primarily meteoritic in origin and not from interplanetary dust particles.  Ponds appeared as contents rose out of the early global ocean but this increasing availability of "targets" for meteorites was offset by declining meteorite bombardment rates.  Moreover, the rapid losses of nucleases to pond seepage during wet periods, and to UV photodissociation during dry periods means that the synthesis of nucleotides and their polymerization into RNA occurred in just one of the few wet-dry cycles.  Under these conditions, RNA polymers likely appeared prior to 4.17 B years ago.  Significance: There are 2 competing hypothesis for the site at which an RNA world emerged: hydrothermal vents in the deep ocean and warm little ponds.  Because the former lacks wet and dry cycles, which are all known to promote polymerization (in this case, of nucleotides into RNA), construct a comprehensive model for the origin of RNA in the latter sites.  The model advances the story and timeline of the RNA world by constraining the source of biomolecules, the environmental conditions, the timescales of reaction, and the emergence of first RNA polymers.

Day 1315

Monday.

1709.10378
Missing baryons in the cosmic web revealed by the Sunyaev-Zel'dovich effect
de Graaff, Cai, Haymans, Peacock

Observations of galaxies and galaxy clusters the local universe can account for only 10% of the baryon content inferred from galaxy measurements of the CMB and from nuclear reactions in the early Universe.  Locating the remaining 90% of baryons has been one of the major challenges in modern cosmology.  Cosmological simulations predict that the 'missing baryons' are spread throughout filamentary structures in the cosmic web, forming a low density gas with temperatures of 1e5-1e7 K.  Previous attempts to observe this warm-hot filamentary gas via X-ray emission or absorption in quasar spectra have proven difficult due to its diffuse and low-temperature nature.  Here, report a 5.1 sigma detection of warm-hot baryons in stacked filaments through the tSZ effect, which arises from the distortion in the CMB spectrum due to ionized gas.  The estimated gas density in these 15 Mph-long filaments is approximately 6x the mean universal baryon density, and overall this can account for ~30% of the total baryon content of the Universe.  This result establishes the presence of ionized gas in LS filaments, and suggests that the missing baryons problem may be resolved via observations of the cosmic web.