Search Publications
Detailed Decomposition of Galaxy Images. II. Beyond Axisymmetric Models
Ho, Luis C.; Rix, Hans-Walter; Peng, Chien Y. +1 more
We present a two-dimensional (2D) fitting algorithm (GALFIT, ver. 3) with new capabilities to study the structural components of galaxies and other astronomical objects in digital images. Our technique improves on previous 2D fitting algorithms by allowing for irregular, curved, logarithmic and power-law spirals, ring, and truncated shapes in othe…
Spectra and Hubble Space Telescope Light Curves of Six Type Ia Supernovae at 0.511 < z < 1.12 and the Union2 Compilation
Panagia, N.; Wang, L.; Lidman, C. +43 more
We report on work to increase the number of well-measured Type Ia supernovae (SNe Ia) at high redshifts. Light curves, including high signal-to-noise Hubble Space Telescope data, and spectra of six SNe Ia that were discovered during 2001, are presented. Additionally, for the two SNe with z > 1, we present ground-based J-band photometry from Gem…
The Structure and Kinematics of the Circumgalactic Medium from Far-ultraviolet Spectra of z ~= 2-3 Galaxies
Pettini, Max; Erb, Dawn K.; Shapley, Alice E. +5 more
We present new results on the kinematics and spatial distribution of metal-enriched gas within ~125 kpc of star-forming ("Lyman break") galaxies at redshifts 2 <~ z <~ 3. In particular, we focus on constraints provided by the rest-frame far-ultraviolet (far-UV) spectra of faint galaxies, and demonstrate how galaxy spectra can be used to obta…
High molecular gas fractions in normal massive star-forming galaxies in the young Universe
Lutz, D.; Förster Schreiber, N. M.; Genzel, R. +19 more
Stars form from cold molecular interstellar gas. As this is relatively rare in the local Universe, galaxies like the Milky Way form only a few new stars per year. Typical massive galaxies in the distant Universe formed stars an order of magnitude more rapidly. Unless star formation was significantly more efficient, this difference suggests that yo…
A study of the gas-star formation relation over cosmic time
Lutz, D.; Förster Schreiber, N. M.; Genzel, R. +19 more
We use the first systematic data sets of CO molecular line emission in z ~ 1-3 normal star-forming galaxies (SFGs) for a comparison of the dependence of galaxy-averaged star formation rates on molecular gas masses at low and high redshifts, and in different galactic environments. Although the current high-z samples are still small and biased towar…
Very High Gas Fractions and Extended Gas Reservoirs in z = 1.5 Disk Galaxies
Daddi, E.; Elbaz, D.; Stern, D. +10 more
We present evidence for very high gas fractions and extended molecular gas reservoirs in normal, near-infrared-selected (BzK) galaxies at z ~ 1.5. Our results are based on multi-configuration CO[2-1] observations obtained at the IRAM Plateau de Bure Interferometer. All six star-forming galaxies observed were detected at high significance. High spa…
Astrometry.net: Blind Astrometric Calibration of Arbitrary Astronomical Images
Hogg, David W.; Lang, Dustin; Blanton, Michael +2 more
We have built a reliable and robust system that takes as input an astronomical image, and returns as output the pointing, scale, and orientation of that image (the astrometric calibration or World Coordinate System information). The system requires no first guess, and works with the information in the image pixels alone; that is, the problem is a …
Galaxy Stellar Mass Assembly Between 0.2 < z < 2 from the S-COSMOS Survey
Kneib, J. -P.; Aussel, H.; Le Floc'h, E. +22 more
We follow the galaxy stellar mass assembly by morphological and spectral type in the COSMOS 2 deg2 field. We derive the stellar mass functions and stellar mass densities from z = 2 to z = 0.2 using 196,000 galaxies selected at F 3.6 µm > 1 µJy with accurate photometric redshifts (σ_{(z_phot-z_spec)/(1+z_spec)}=…
An absolutely calibrated Teff scale from the infrared flux method. Dwarfs and subgiants
Asplund, M.; Casagrande, L.; Meléndez, J. +2 more
Various effective temperature scales have been proposed over the years. Despite much work and the high internal precision usually achieved, systematic differences of order 100 K (or more) among various scales are still present. We present an investigation based on the infrared flux method aimed at assessing the source of such discrepancies and pin…
The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150Msolar stellar mass limit
Parker, Richard J.; Crowther, Paul A.; Goodwin, Simon P. +4 more
Spectroscopic analyses of hydrogen-rich WN5-6 stars within the young star clusters NGC3603 and R136 are presented, using archival Hubble Space Telescope and Very Large Telescope spectroscopy, and high spatial resolution near-IR photometry, including Multi-Conjugate Adaptive Optics Demonstrator (MAD) imaging of R136. We derive high stellar temperat…