Day 1064

Friday.  Monday.


1603.03494
The spatial distribution of ultra diffuse galaxies within large scale structures
Roman, Trujillo

SDSS Stripe82, 8x8 Mpc^2 around Abell 168 (z=0.045) -- check distribution of UDGs around it.  Find that UDGs are located within the large scale structures that comprise the A168 overdensity.  Approximately 42% of the UDGs analysed inhabit the cluster region, ~7±3% in the core and ~35±7% in the outskirts whereas the remaining UDGs are found outside the main overdensity: ~19±5% in groups and ~40% in filaments.  UDGs structural properties gradually change form the lowest to the densest regions with a decrease of their stellar mass by a factor of ~1.5, an increase of their Sersic index n by a factor of ~1.25 and a decrease in their tis ratio (b/a) by a factor of ~1.13.  This transformation supports the idea that UDGs probably form outside clusters and are later on accreted towards the cluster's central regions, where they are finally destroyed by disruption.  Finally, the spatial distribution of the UDGs is very similar to the one found for dwarf galaxies but significantly different for the distribution of galaxies like the MW, suggesting that UDGs could be bona fide dwarfs and not failed L* galaxies.


1603.03709
AKARI far-infrared maps of the zodiacal dust bands
Ootsubo, et al

Zodiacal emission is thermal emission from interplanetary dust.  Its contribution of the sky brightness is non-negligible in the region near the ecliptic plane, even in the far-IR wavelength regime.  Analyze zodiacal emission observed by the AKARI FIR all-sky survey, which covers 97% of the entire sky at arcminute-scale resolution in 4 photometric bands, with central wavelengths of 65, 90, 140, and 160 um.  AKARI detected small-scale structures in the zodiacal dust cloud, including the asteroidal dust bands and the circumsolar ring, at FIR wavelengths.  Although the smooth component of the zodiacal emission structure in the FIR sky can be reproduced well by models based on existing FIR observations, previous zodiacal emission models have discrepancies in the small-scale structures compared with observations.  Investigate the geometry of the small-scale dust-band structures in the AKARI FIR all-sky maps and construct template maps of the asteroidal dust bands and the circumsolar ring components based on the AKARI FIR maps.  In the maps, ±1.4deg, ±2.1 deg and ±10 deg asteroidal dust-band structures are detected in the 65um and 90um bands.  A possible ±17deg band may also have been detected.  No evident dust-band structures are identified in either the 140um or the 160um bands.  By subtracting the dust-band templates constructed in this paper, can achieve a similar level of flux calibration of the AKARI FIR all-sky maps in the |beta|<40 deg region to that in the region for |beta|>40 deg.