Day 1072

Monday.

1603.07734
The rotation of the hot gas around the Milky Way
Hodges-Klick, Miller, Bregman

The hot gaseous halos of galaxies likely contain a large amount of mass and are an integral part of galaxy formation and evolution.  The MW has a 2e6 K halo that is detected in emission and by absorption in the OVII resonance line against bright background AGNs, and for which the best current model is an extended spherical distribution.  Using XMM-Newton RGS data, measure the Doppler shifts of the OVII absorption-line centroids toward an ensemble of AGNs. These Doppler shifts constrain the dynamics of the hot halo, ruling out a stationary halo at about 3 sigma and a corotating halo at 2 sigma, and leading to a best-fit rotational velocity of 183±41 km/s for an extended halo model.  These results suggest that the hot gas rotates and that it contains an amount of angular momentum comparable to that in the stellar disk.  Examine the possibility of a model with a kinematically distinct disk and spherical halo.  To be consistent with the emission-line X-ray data the disk must contribute less than 10% of the column density, implying that the Doppler shifts probe motion in the extended hot halo.


1603.07818
A pseudo-spectrum analysis of galaxy-galaxy lensing
Hikage, Oguri

Present the application of the pseudo-spectrum method to gg lensing.  Derive explicit expressions for the pseudo-spectrum analysis of the galaxy-shear cross spectrum, which is the Fourier space counterpart of the stacked gg lensing profile.  The pseudo-spectrum method corrects observational issues such as the survey geometry, masks of bright stars and their spikes, and inhomogeneous noise, which distort the spectrum and also mix the E-mode and the B-mode signals.  Using ray-tracing simulations in N-body sims including realistic masks, confirm that the pseudo-spectrum method successfully recovers the input galaxy-shear cross spectrum.  Also investigate the covariance of the galaxy-shear cross spectrum using the ray-tracing sims to show that there is an excess covariance relative to the Gaussian covariance at small scales where the shot noise is dominated in the Gaussian approximation.  Find that the excess of the covariance is consistent with the expectation from the halo sample variance (HSV), which originates from the matter fluctuations as scales larger than the survey area.  Apply the pseudo-spectrum method to the observational data of CFHTLenS shear catalogue and BOSS CMASS and LOWZ galaxies.  The galaxy-shear cross spectra are significantly detected at the level of 7-10 sigma using the analytic covariance with the HSV contribution included.  Also confirm that the observed spectra are consistent with the halo model predictions with the halo occupation distribution parameters estimated from previous work.  This work demonstrate the viability of gg lensing analysis in Fourier space.