1602.03909
Evolution of intrinsic water in the SFR-stellar mass correlation at 0.5<z<3
Kurczynski et al
Present estimates of intrinsic scatter in the SFR-M* correlation in the 0.5<z<3.0 and in the mass range 1e7<M*<1e11 Msun. Utilize photometry in HUDF12, UVUDF campaigns and CANDELS/GOODS-S. Estimate SFR, M* from broadband SEDs and the best available redshifts. The maximum depth of the UDF photometry (F160W 29.9 AB, 5 sigma depth) probes the SFR-M* correlation down to M*~1e7 Msun, a factor of 10-100x lower in M* than previous studies, and comparable to dwarf galaxies in the local universe. Find the slope of the SFR-M* relationship to be near unity at all redshifts and the normalization to decrease with cosmic time. Find a moderate increase in intrinsic scatter wth cosmic time from 0.2 to 0.4 dex across the epoch of peak cosmic SF. None of the redshift bins show a statistically significant increase in intrinsic scatter at low mass. However, it remains possible that intrinsic scatter increases at low mass on timescales shorter than ~100 Myr. Results are consistent with a picture of gradual and self-similar assembly of galaxies across more than 3 orders of magnitude in stellar mass from as low as 1e7 Msun.
1602.04002
An over massive dark halo around an ultra-diffuse galaxy in the Virgo cluster
Beasley, et al
UDG's have the sizes of giant galaxies but the luminosities of dwarfs. A key to understanding their origins comes from their total masses, but their low surface brightnesses generally prohibit dynamical studies. Report the first such measurements for a UDG based on its globular cluster system dynamics and size. From 7 GCs, measure a mean systemic velocity 1071±15 km/s, thereby confirming a Virgo-cluster association. Measure a velocity dispersion of 33+16-10 km/s within 8.1 kpc, corresponding to an enclosed mass of (4.5±2.8)e9 Msun and a g-band M/L=106+126-54. From the cumulative mass curve, along with the GC numbers, estimate a viral mass of 8e10 Msun, yielding a dark-to-stellar mass fraction of ~3000. Show that this UDG is an outlier in M*-Mhalo relations, suggesting extreme stochasticity in relatively massive SF'ing halos in clusters. Discuss how counting GCs offers an efficient route to determining viral masses for UDGs.
1602.04156
Pan-STARRS and PESSTO search for the optical counterpart to the LIGO gravitational wave source GW150914
Smart et al
No promising optical counterpart to the GW event.
1602.04180
INTEGRAL upper limits on gamma-ray emission associated with the gravitational wave event GW150914
Savchenko, et al
Upper limits on gamma and hard X-ray. Hard X-ray = EM component from 2e-8 erg/cm2 to 1e-6 erg/cm2 in the 75 keV to 2 MeV range. Constraint: E_gamma / E_GW < 1e-6.
1602.04199
A dark energy camera search for missing supergiants in the LMC after the advanced LIGO gravitational event GW150914
Annis, et al
Pointed DECam shortly after the GW event, covering the LMC area looking for direct stellar collapse to a BH. None of the 152 LMC luminous red supergiants have disappeared. Recovered all from existing catalogs of red supergiants, yellow supergiants, WR stars, and luminous blue variable stars, that were inside the imaging area. Conclude that it was unlikely that GW150914 was caused by the core collapse of a supergiant in the LMC.
No comments:
Post a Comment