astro-ph coffee suggested papers for Wed, Feb 12 at 10:00:00 AM and Fri, Feb 07, 2014 at 11:30:00 AM

astro-ph coffee will be held at the date and time above. Some suggested papers of interest are listed below.

5 Feb 2014

Imaging Atmosphere Cherenkov Telescopes (IACT) are arrays of very large optical telescopes that are well-suited for rapid photometry of bright sources. I investigate their potential in observing stellar occultations by small objects in the outer Solar System, Transjovian Objects (TJOs). These occultations cast diffraction patterns on the Earth. Current IACT arrays are capable of detecting objects smaller than 100 meters in radius in the Kuiper Belt and 1 km radius out to 5000 AU. The future Che...

5 Feb 2014

Models and simulations of the epoch of reionization predict that spectra of the 21-cm transition of atomic hydrogen will show a clear fluctuation peak, at a redshift and scale, respectively, that mark the central stage of reionization and the characteristic size of ionized bubbles. This is based on the assumption that the cosmic gas was heated by stellar remnants - particularly X-ray binaries - to temperatures well above the cosmic microwave background at that time (~ 30 K). Here we show instea...

5 Feb 2014

We report HCN J=4-3, HCO+ J=4-3, and CS J=7-6 observations in 20 nearby star-forming galaxies with the Acatama Pathfinder EXperiment 12-m telescope. Combined with 4 HCN, 3 HCO+, and 4 CS detections in literature, we probe the empirical link between the luminosity of molecular gas (L_gas) and that of infrared emission (L_IR), up to the highest gas densities (10^6 - 10^8 cm-3) that have been probed so far. For nearby galaxies with large radii, we measure the IR luminosity within the submm beam-si...

30 Jan 2014

The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of ~0.25 deg^2 with ~900 HST orbits spread across 5 fields over 3 years. Within these survey images we discovered 65 supernovae (SN) of all types, out to z~2.5. We classify ~24 of these as Type Ia SN (SN Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of 6 SN). Here we present a mea...

3 Feb 2014

We present in this letter the first analysis of a z~8 galaxy candidate found in the Hubble and Spitzer imaging data of Abell 2744, as part of the Hubble Frontier Fields legacy program. We applied the most commonly-used methods to select exceptionally high-z galaxies by combining non-detection and color-criteria using seven HST bands. We used GALFIT on IRAC images for fitting and subtracting contamination of bright nearby sources. The physical properties have been inferred from SED-fitting using...

3 Feb 2014

We present an integral field spectroscopic study of the Luminous Infrared Galaxy (LIRG) NGC 7130, a known starburst-AGN composite galaxy. We employ standard emission line ratio diagnostics and maps of velocity dispersion and velocity field to investigate how the dominant ionising sources change as a function of radius. From the signatures of both star formation and AGN activity we show that NGC 7130 is a remarkably clean case of starburst-AGN mixing. We find a smooth transition from AGN dominat...

4 Feb 2014

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations in the dust continuum (690 GHz, 0.45 mm) and 12CO J=6-5 spectral line emission, of the transitional disks surrounding the stars SAO 206462 and SR 21. These ALMA observations resolve the dust-depleted disk cavities and extended gaseous disks, revealing large-scale asymmetries in the dust emission of both disks. We modeled these disks structures with a ring and an azimuthal gaussian, where the azimuthal gaussian is motiva...

4 Feb 2014

In this Letter, we report the discovery of SN2014J in the nearby galaxy M82. Given its proximity, it offers the best opportunity to date to study a thermonuclear supernova over a wide range of the electromagnetic spectrum. The first set of optical, near-IR and mid-IR observations of SN2014J, orchestrated by the intermediate Palomar Transient Factory (iPTF), show that SN2014J is a spectroscopically normal Type Ia supernova, albeit exhibiting high-velocity features in its spectrum and heavily red...

3 Feb 2014

We present results from near-infrared spectroscopy of 26 emission-line galaxies at z ~ 2 obtained with the FIRE spectrometer on the Magellan Baade telescope. The sample was selected from the WISP survey, which uses the near-infrared grism of the Hubble Space Telescope Wide Field Camera 3 to detect emission-line galaxies over 0.3 < z < 2.3. Our FIRE follow-up spectroscopy (R~5000) over 1.0-2.5 micron permits detailed measurements of physical properties of the z~2 emission-line galaxies. Du...

29 Jan 2014

The excitation of the gas phase of the interstellar medium can be driven by various mechanisms. In galaxies with an active nucleus, such as Seyfert galaxies, both radiative and mechanical energy from the central black hole, or the stars in the disk surrounding it may play a role. We investigate the relative importance and range of influence of the active galactic nucleus for the excitation of ionized and molecular gas in the central kiloparsec of its host galaxy. We present H- and K-band long-s...

31 Jan 2014

Brown dwarfs -- substellar bodies more massive than planets but not massive enough to initiate the sustained hydrogen fusion that powers self-luminous stars -- are born hot and slowly cool as they age. As they cool below about 2,300 K, liquid or crystalline particles composed of calcium aluminates, silicates and iron condense into atmospheric 'dust', which disappears at still cooler temperatures (around 1,300 K). Models to explain this dust dispersal include both an abrupt sinking of the entire...

30 Jan 2014

The next generation of giant-segmented mirror telescopes ($>$ 20 m) will enable us to observe galactic nuclei at much higher angular resolution and sensitivity than ever before. These capabilities will introduce a revolutionary shift in our understanding of the origin and evolution of supermassive black holes by enabling more precise black hole mass measurements in a mass range that is unreachable today. We present simulations and predictions of the observations of nuclei that will be made w...

astroph.py v0.98.9fbd based on the original astroph.py. Updated 2014/02/06 17:39:52

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