Day 1082

Thursday.  Friday.

1604.03934
Large-scale imprint of relativistic effects in the cosmic magnification
Duniya

Apart from the known WL effect, the cosmic magnification acquires relativistic corrections owing to: Doppler, ISW, time-delay and other (local) gravitational potential effects, respectively.  These corrections grow on very large scales and high redshifts z, which will be [within] reach of forthcoming surveys.  In this work, these relativistic corrections are investigated in the magnification angular power spectrum, using both (standard) non-interacting dark energy (DE), and interacting dark energy (IDE).  It is found that for non-interaction DE, the relativistic corrections can boost the magnification large-scale power by ~40% at z=3, and increases at lower z.  It is also found that the IDE effect is sensitive to the relativistic corrections in the magnification power spectrum, particularly at low z---which will be crucial for constraints on IDE.  Moreover, the results show that if relativistic corrections are not taken into account, this may lead to an incorrect estimate of the large-scale imprint of IDE in the cosmic magnification: including the relativistic corrections can enhance the true potential of the cosmic magnification as a cosmological probe.


1604.03937
Evidence for the alignment of quasar radio polarizations with large quasar group axes
Pelgrims, Hutsemékers

Recently, evidence has been presented for the polarization vectors from quasars to preferentially align with the axes of the large quasar groups (LQG) to which they belong.  This report was based on observations made at optical wavelengths for two large quasar groups at z~1.3.  The correlation suggests that the spin axes of quasars preferentially align with their surrounding large-scale structure that is assumed to be traced by the LQGs.  Here, consider a large sample of LQGs build from SDSS DR7 quasar catalog in 1.0<z<1.8.  For quasars embedded in this sample, collected radio polarization measurements with the goal to study possible correlations between quasar polarization vectors and the major axis of their host LQGs.  Assuming the radio polarization vector is perpendicular to the quasar spin axis, found that the quasar spin axis is preferentially parallel to the LQG major axis inside LQGs that have at least 20 members.  This result independently supports the observations at optical wavelengths.  Additionally find that when the richness of an LQG decreases, the quasar spin axis becomes preferentially perpendicular to the LQG major axis and that no correlation is detected for quasar groups with fewer than 10 members.


1604.03957
RESOLVE and ECO: the halo mass-dependent shape of galaxy stellar ad baryonic mass functions
Eckert, et al

Present galaxy stellar and baryonic (stars plus cold gas) mass functions (SMF and BMF) and their halo mass dependence for 2 volume-limited data sets.  The first, RESOLVE-B, coincides with the Stripe 82 footprint and is extremely complete down to baryonic mass Mbary~1e9.1 Msun, probing the gas-rich dwarf regime below Mbary~1e10 Msun.  The second, ECO, covers a ~40 times larger volume (containing RESOLVE-A) and is complete to Mbary~1e9.4 Msun.  To construct the SMF and BMF, implement a new "cross-bin sampling" technique with MC sampling from the full likelihood distributions of stellar or baryonic mass.  The SMFs exhibit the "plateau" feature staring below Mstar~1e10 Msun that has been described in prior work.  However, the BMF fills in this feature and rises as a straight power law below ~1e10 Msun, as gas-dominated galaxies become the majority of the population.  Nonetheless, the low-mass slope of the BMF is not as steep as that of the theoretical DM halo MF.  Moreover, assign group halo masses by abundance matching, finding that the SMF and BMF separated into 4 physically motivated halo mass regimes reveal complex structure underlying the simple shape of the overall MFs.  In particular, the satellite MFs are depressed below the central galaxy MF "humps" in groups with mass <1e13.5 Msun yet rise steeply in clusters.  The results suggest that satellite destruction and/or stripping are active from the point of nascent group formation.  Show that the key role of groups in shaping MFs enables reconstruction of a given survey's SMF or BMF based on its group halo mass distribution.