astro-ph coffee suggested papers for Thu, Apr 18, 2013 at 03:00:00 PM

astro-ph coffee will be held at the date and time above in the PAB 3rd-floor reading room. Some suggested papers of interest are listed below.

17 Apr 2013

The Hubble Space Telescope (HST) Treasury Program on the Orion Nebula Cluster has used 104 orbits of HST time to image the Great Orion Nebula region with the Advanced Camera for Surveys (ACS), the Wide-Field/Planetary Camera 2 (WFPC2) and the Near Infrared Camera and Multi Object Spectrograph (NICMOS) instruments in 11 filters ranging from the U-band to the H-band equivalent of HST. The program has been intended to perform the definitive study of the stellar component of the ONC at visible wave...

16 Apr 2013

In the absence of spectra, fitting template model spectra to observed photometric fluxes, known as Spectral Energy Distribution (SED) fitting, has become the workhorse for identifying high-z galaxies. In this paper, we present an analysis of the most recent and possibly most distant galaxies discovered in the Hubble Ultra Deep Field using a more robust method of redshift estimation based on Markov Chain Monte Carlo fitting (MCMC), rather than relying on the redshift of "best fit" models obtaine...

15 Apr 2013

The Transit Timing Variations (TTVs) can be used as a diagnostic of gravitational interactions between planets in a multi-planet system. Many Kepler Objects of Interest (KOIs) exhibit significant TTVs, but KOI-142.01 stands out among them with an unrivaled, 12-hour TTV amplitude. Here we report a thorough analysis of KOI-142.01's transits. We discover periodic Transit Duration Variations (TDVs) of KOI-142.01 that are nearly in phase with the observed TTVs. We show that KOI-142.01's TTVs and TDV...

15 Apr 2013

Star-forming galaxies at redshifts z>6 are likely responsible for the reionization of the universe, and it is important to study the nature of these galaxies. We present three candidates for z~7 Lyman-break galaxies (LBGs) from a 155 arcmin^2 area in the CANDELS/COSMOS field imaged by the deep FourStar Galaxy Evolution (zFourGE) survey. The FourStar medium-band filters provide the equivalent of R~10 spectroscopy, which cleanly distinguishes between z~7 LBGs and brown dwarf stars. The distinc...

9 Apr 2013

We investigate the link between AGN activity, star-formation and stellar mass of the host galaxy at 0<z<1, looking for spectroscopic traces of AGN and aging of the host. This work provides an extension of the existing studies at z<0.1 and contributes to shed light on galaxy evolution at intermediate redshifts. We used the zCOSMOS 20k data to create a sample of galaxies at z<1. We divided the sample in several mass-redshift bins to obtain stacked galaxy spectra with an improved S/N. ...

15 Apr 2013

We present abundance measurements from 26 emission-line selected galaxies at z~0.6-0.7. By reaching stellar masses as low as 10^8 M_{\sun}, these observations provide the first measurement of the intermediate redshift mass-metallicity (MZ) relation below 10^9 M_{\sun} For the portion of our sample above M > 10^9 M_{\sun} (8/26 galaxies), we find good agreement with previous measurements of the intermediate redshift MZ relation. Compared to the local relation, we measure an evolution that cor...

15 Apr 2013

Massive present-day early-type (elliptical and lenticular) galaxies probably gained the bulk of their stellar mass and heavy elements through intense, dust-enshrouded starbursts - that is, increased rates of star formation - in the most massive dark matter halos at early epochs. However, it remains unknown how soon after the Big Bang such massive starburst progenitors exist. The measured redshift distribution of dusty, massive starbursts has long been suspected to be biased low in redshift owin...

Web Article:

28 Mar 2013

An extrapolation of the genetic complexity of organisms to earlier times suggests that life began before the Earth was formed. Life may have started from systems with single heritable elements that are functionally equivalent to a nucleotide. The genetic complexity, roughly measured by the number of non-redundant functional nucleotides, is expected to have grown exponentially due to several positive feedback factors: gene cooperation, duplication of genes with their subsequent specialization, a...

10 Apr 2013

In this paper, the detectability of habitable exomoons orbiting around giant planets in M-dwarf systems using Transit Timing Variations (TTVs) and Transit Timing Durations (TDVs) with Kepler-class photometry is investigated. Light curves of systems with various configurations were simulated around M-dwarf hosts of mass 0.5 Msun and radius 0.55 Rsun. Jupiter-like giant planets which offer the best potential for hosting habitable exomoons were considered with rocky super-Earth-mass moons. The det...

10 Apr 2013

Motivated by the reported dearth of debris discs around M stars, we use survival models to study the occurrence of planetesimal discs around them. These survival models describe a planetesimal disc with a small number of parameters, determine if it may survive a series of dynamical processes and compute the associated infrared excess. For the WISE satellite, we demonstrate that the dearth of debris discs around M stars may be attributed to the small semi-major axes generally probed if either: 1...

12 Apr 2013

We explore the minimum distance from a host star for an exoplanet to be potentially habitable, in order to maximize future chances of finding other habitable worlds. We find that the inner edge of the Habitable Zone (HZ) for hot desert worlds is at 0.5 AU around a solar-like star (well within the orbit of Venus). The relative humidity is the key controlling factor in determining the inner edge distance because water vapor has a strong impact on the greenhouse warming of the atmosphere, yet too ...

11 Apr 2013

An LSST-like survey of the Galactic plane (deep images every 3-4 days) could probe the Galactic distribution of planets by two distinct methods: gravitational microlensing of planets beyond the snow line and transits by planets very close to their hosts. The survey would identify over 250 disk-lens/disk-source microlensing events per year that peak at r<19, including 10% reaching the high magnification A>100 that makes them especially sensitive to planets. Intensive followup of these even...

11 Apr 2013

We evaluate the extent to which newly detected exoplanetary systems containing at least four planets adhere to a generalized Titius-Bode (TB) relation. We find that the majority of exoplanet systems in our sample adhere to the TB relation to a greater extent than the Solar System does, particularly those detected by the Kepler mission. We use a generalized TB relation to make a list of predictions for the existence of 126 additional exoplanets in 64 multiple-exoplanet systems: 62 candidates fro...

11 Apr 2013

Lyman break galaxies (LBGs) represent one of the kinds of star-forming galaxies that are found in the high-redshift universe. The detection of LBGs in the FIR domain can provide very important clues on their dust attenuation and total SFR, allowing a more detailed study than those performed so far. In this work we explore the FIR emission of a sample of 16 LBGs at z ~ 3 in the GOODS-North and GOODS-South fields that are individually detected in PACS-100um or PACS-160um. These detections demonst...

11 Apr 2013

We present new quasars discovered in the vicinity of the Andromeda and Triangulum galaxies with the LAMOST during the 2010 and 2011 observational seasons. Quasar candidates are selected based on the available SDSS, KPNO 4 m telescope, XSTPS optical, and WISE near infrared photometric data. We present 509 new quasars discovered in a stripe of ~135 sq. deg from M31 to M33 along the Giant Stellar Stream in the 2011 pilot survey datasets, and also 17 new quasars discovered in an area of ~100 sq. de...

10 Apr 2013

Galaxy counts and recent measurements of the luminosity density in the near-infrared (NIR) have indicated the possibility that the local universe may be under-dense on scales of several hundred megaparsecs. The presence of a large-scale under-density in the local universe could introduce significant biases into the interpretation of cosmological observables, and, in particular, into the inferred effects of dark energy on the expansion rate. Here we measure the K-band luminosity density as a fun...

10 Apr 2013

The best gravitational lenses for detecting distant galaxies are those with the largest mass concentrations and the most advantageous configurations of that mass along the line of sight. Our new method for finding such gravitational telescopes uses optical data to identify projected concentrations of luminous red galaxies (LRGs). LRGs are biased tracers of the underlying mass distribution, so lines of sight with the highest total luminosity in LRGs are likely to contain the largest total mass. ...

astroph.py v0.91ijc based on the original astroph.py. Updated 2013/04/18 11:26:48

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