Day 566

Friday. …. Wednesday.

1312.2313
Precision astronomy with imperfect fully depleted CCDs -- an introduction and a suggested lexicon
Stubbs

Summary of challenges of making precision astronomical measurements using deeply depleted (thick) CCDs.  While thick CCDs provide definite advantages in terms of increased quantum efficiency at NIR wavelengths, and reduced fringing from atmospheric emission lines, these devices also exhibit undesirable features that pose a challenge to precision determination of the positions, fluxes, and shapes of astronomical objects, and features in astronomical spectra.  Many of the effects seen in these devices arise from lateral electoral fields within the detector, that produce charge transport anomalies that have been previously misinterpreted as quantum efficiency variations.  Performing simplistic flat-fielding introduces systematic errors in the image processing pipeline.  One measurement challenge is devising a calibration method that can distinguish genuine quantum efficiency variations from charge transport effects.  Given the scientific benefits of improving both the precision and accuracy of astronomical measurements, need to identify, characterize and overcome these various detector artifacts.  In retrospect, many of the detector features first identified in thick CCDs also afflict measurements made with more traditional CCD detectors, albeit often at a reduced level.  Provide a qualitative overview of the physical effects of the physical effects believed to be responsible for the observed device properties, and provide some perspective for the work that lies ahead.  Establishing a clear and consistent vocabulary when describing these various detector features, and make some suggestions for a standard lexicon based on discussions at the workshop.

1312.2330
A provocative summary: is there any unified model for triggering active galactic nuclei?
Taniguchi

Summary of "galaxy mergers in an evolving universe".  Conference covers 1) mergers at low z, 2) merger dynamics and numerical simulations, 3) mergers in galaxy evolution, 4) mergers and AGNs, 5) mergers at high z and submm galaxies, 6) feedback from starbursts and AGNs, 6) chemical evolution of galaxies, and 7) results from new surveys.  "Is there any unified model for triggering AGN?"  Given key observational properties of galaxies with AGNs, a possible unified model is discussed as an evolutionary model from starbursts to AGNs based on minor and major mergers between/among galaxies.

1312.2373
Magnetic fields in stars: origin and impact
Langer

Various types of B-fields occur in stars: small scale fields, large scale fields, and internal toroidal fields.  While the latter may be ubiquitous in stars due to differential rotation, small scale fields (spots) may be associated with envelope convection in all low and high mass stars.  The stable large scale fields found in only about 10% of intermediate mass and massive stars may be understood as a consequence of dynamical binary interaction, e.g., the merging of two stars in a binary.  Relate these ideas to B-fields in white dwarfs and neutron stars, and to their role in core-collapse and thermonuclear supernova explosions.

1312.2399
An HI study of NGC 3521 - a galaxy with a slow-rotating halo
Elson

The anomalous HI lags the regular HI by ~25-125 km/s; possible location of anomalous HI strongly suggest it to be distributed in a thick disc with a scale height of ~3.5 kpc, constituting a slow-rotating halo gas component (consistent with nearby galaxies), spatially coincident with the inner regions of the stellar disc where the SFR is highest.  It is most likely a galactic fountain that has deposited gas from the from the disc of the galaxy into the halo.

1312.2417
Massive star-forming host galaxies of quasars on SDSS stripe 82
Matsuoka, Strauss, Price, DiDonato

Stellar properties of 800 optically luminous, unobscured galaxies at z<0.6 analyzed.  Decompose into nucleus and host galaxy from PSF and Sersic models.  Systematic errors in measured absolute magnitudes and colors are 0.5 and 0.1 mag respectively, with simulated quasar images.  Effect of quasar light scattered by the ISM is also addressed.  The measured quasar-to-galaxy ratio in total flux decreases toward longer wavelengths, from ~8 in the u band to ~1 in the i and z bands.  Find that SDSS quasars are hosted exclusively by massive galaxies (M*>1e10 Msun), which is consistent with previous results for less luminous narrow-line (obscured) AGNs.  The quasar hosts are very blue and almost absent on the red sequence, showing stark contrast to the color-magnitude distribution of normal galaxies.  The fact that more powerful AGNs reside in galaxies with higher SF efficiency may indicate that negative AGN feedback, if it exists, is not concurrent with the most luminous phase of AGNs.  Also find positive correlation between the mass of SMBHs, and host stellar mass, but the M_BH-M* relation is offset toward large M_BH or small M* compared to the local relation.  While this could indicate that SMBHs grow earlier than do their host galaxies, such an argument is not conclusive, as the effect may be dominated by observational biases.