Search Publications
Spitzer MIPS Infrared Imaging of M31: Further Evidence for a Spiral-Ring Composite Structure
Barmby, P.; Krause, O.; Gordon, K. D. +16 more
New images of M31 at 24, 70, and 160 µm taken with the Multiband Imaging Photometer for Spitzer (MIPS) reveal the morphology of the dust in this galaxy. This morphology is well represented by a composite of two logarithmic spiral arms and a circular ring (radius ~10 kpc) of star formation offset from the nucleus. The two spiral arms appear t…
The XMM Cluster Survey: A Massive Galaxy Cluster at z = 1.45
Conselice, Christopher J.; Hilton, Matt; Stanford, S. A. +14 more
We report the discovery of XMMXCS J2215.9-1738, a massive galaxy cluster at z=1.45, which was found in the XMM Cluster Survey. The cluster candidate was initially identified as an extended X-ray source in archival XMM data. Optical spectroscopy shows that six galaxies within a ~60" diameter region lie at z=1.45+/-0.01. Model fits to the X-ray spec…
The Detailed Star Formation History in the Spheroid, Outer Disk, and Tidal Stream of the Andromeda Galaxy
Ferguson, Henry C.; Brown, Thomas M.; Rich, R. Michael +5 more
Using HST ACS, we have obtained deep optical images reaching stars well below the oldest main-sequence turnoff in the spheroid, tidal stream, and outer disk of Andromeda. We have reconstructed the star formation history in these fields by comparing their color-magnitude diagrams to a grid of isochrones calibrated to Galactic globular clusters obse…
Observations of Thick Disks in the Hubble Space Telescope Ultra Deep Field
Elmegreen, Bruce G.; Elmegreen, Debra Meloy
The vertical profiles of chain and spiral galaxies in the Hubble Space Telescope Ultra Deep Field (UDF) are fit to sech2(z/z0) functions convolved with stellar profiles in order to measure the disk scale heights z0 in four passbands. The bulge regions of the spiral galaxies are avoided. Photometric redshifts give a…
Coronal Holes, Jets, and the Origin of 3He-rich Particle Events
Pick, M.; Mason, G. M.; Wang, Y. -M.
Using magnetograph measurements, coronal field extrapolations, and imaging observations, we investigate the solar origins of 25 3He-rich particle events from the period 1997-2003. In essentially every case we find that the source of the impulsive solar energetic particles (SEPs) lies next to a coronal hole containing Earth-directed open…
Minkowski's Object: A Starburst Triggered by a Radio Jet, Revisited
Stanford, S. A.; Morganti, Raffaella; Oosterloo, Tom +8 more
We present neutral hydrogen, ultraviolet, optical, and near-infrared imaging, and optical spectroscopy, of Minkowski's Object (MO), a star-forming peculiar galaxy near NGC 541. The observations strengthen evidence that star formation in MO was triggered by the radio jet from NGC 541. Key new results are the discovery of a 4.9×108 M…
Exploring Brown Dwarf Disks: A 1.3 mm Survey in Taurus
Wood, Kenneth; Jayawardhana, Ray; Scholz, Alexander
We have carried out sensitive 1.3 mm observations of 20 young brown dwarfs in the Taurus star-forming region, representing the largest sample of young substellar objects targeted in a deep millimeter-continuum survey to date. Under standard assumptions, the masses of brown dwarf disks range from <~0.4 to several Jupiter masses. Their relative d…
Spitzer IRAC Confirmation of z850-Dropout Galaxies in the Hubble Ultra Deep Field: Stellar Masses and Ages at z ~ 7
Labbé, Ivo; Illingworth, G. D.; Franx, M. +1 more
Using Spitzer IRAC mid-infrared imaging from the Great Observatories Origins Deep Survey, we study z850-dropout sources in the Hubble Ultra Deep Field. After carefully removing contaminating flux from foreground sources, we clearly detect two z850 dropouts at 3.6 and 4.5 µm, while two others are marginally detected. The…
Discovery of an Extraordinarily Massive Cluster of Red Supergiants
MacKenty, John W.; Figer, Donald F.; Kudritzki, Rolf P. +4 more
We report the discovery of an extraordinarily massive young cluster of stars in the Galaxy, having an inferred total initial cluster mass comparable to the most massive young clusters in the Galaxy. Using IRMOS, 2MASS, and Spitzer observations, we conclude that there are 14 red supergiants in the cluster, compared with five, in what was previously…
The Morphological Diversities among Star-forming Galaxies at High Redshifts in the Great Observatories Origins Deep Survey
Papovich, Casey; Dickinson, Mark; Ferguson, Henry C. +8 more
We used the deep, multiwavelength images obtained by the Great Observatories Origins Deep Survey (GOODS) to identify ~4700 Lyman break galaxies (LBGs) at z>2.5, and 292 starburst galaxies at z~1.2. We present the results from morphological analysis based on light profile shape and ellipticity for ~1333 of the most luminous LBGs. About 40% of LB…