Search Publications
Seyfert's Sextet: a Slowly Dissolving Stephan's Quintet?
Yun, M. S.; Plana, H.; Iovino, A. +7 more
We present a multiwavelength study of the highly evolved compact galaxy group known as Seyfert's Sextet (HCG79: SS). We interpret SS as a 2-3 Gyr more evolved analog of Stephan's Quintet (HCG92: SQ). We postulate that SS formed by sequential acquisition of 4-5 primarily late-type field galaxies. Four of the five galaxies show an early-type morphol…
Changing Characteristics of Jupiter's Little Red SPOT
Baines, K. H.; Pantin, E.; Stern, S. A. +12 more
The Little Red Spot (LRS) in Jupiter's atmosphere was investigated in unprecedented detail by the New Horizons spacecraft together with the Hubble Space Telescope (HST) and the Very Large Telescope (VLT). The LRS and the larger Great Red Spot (GRS) of Jupiter are the largest known atmospheric storms in the solar system. Originally a white oval, th…
HiRes Deconvolution of Spitzer Infrared Images
Marsh, K. A.; Beichman, C. A.; Velusamy, T. +2 more
Spitzer provides unprecedented sensitivity in the infrared (IR), but the spatial resolution is limited by a relatively small aperture (0.85 m) of the primary mirror. In order to maximize the scientific return it is desirable to use processing techniques which make the optimal use of the spatial information in the observations. We have developed a …
Rotational Velocities for Early-Type Stars in the Young Large Magellanic Cloud Cluster R136: Further Study of the Relationship Between Rotation Speed and Density in Star-Forming Regions
Cunha, K.; Olsen, K.; Daflon, S. +3 more
We present the results of a study aimed at assessing the distribution of rotation speeds, N(v sin i) among O- and early B-type stars located in R136, a young (t ~ 1-4 Myr) cluster in the Large Magellanic Cloud (LMC) characterized by a stellar density at least three times that of the densest Galactic clusters in which stellar rotational velocities …
Evolved Stars in the Core of the Massive Globular Cluster NGC 2419
Sandquist, Eric L.; Hess, Jordan M.
We present an analysis of optical and ultraviolet Hubble Space Telescope photometry for evolved stars in the core of the distant massive globular cluster NGC 2419. We characterize the horizontal branch (HB) population in detail including corrections for incompleteness on the long blue tail. The majority of the HB stars can be identified with two m…
Stellar Populations in the Andromeda V Dwarf Spheroidal Galaxy
Sarajedini, Ata; Mancone, Conor
Using archival imaging from the Wide Field Planetary Camera 2 aboard the Hubble Space Telescope, we investigate the stellar populations of the Local Group dwarf spheroidal Andromeda V—a companion satellite galaxy of M31. The color-magnitude diagram extends from above the first ascent red giant branch (RGB) tip to approximately 1 mag below the hori…
Observational Biases Masquerading as Cosmological Effects? a Cautionary tale about Blue Tilts and Other Trends in Globular Cluster Systems
Kundu, Arunav
The high spatial resolution of the Hubble Space Telescope (HST) has led to tremendous progress in many areas of astronomy. The ability of the HST to peer into the bright inner regions of galaxies and distinguish between globular clusters (GCs) and background objects has been particularly beneficial to the study of clusters. However, the very virtu…
HE 1113-0641: The Smallest-Separation Quadruple Lens Identified by a Ground-Based Optical Telescope
Wisotzki, Lutz; Schechter, Paul L.; Blackburne, Jeffrey A.
The Hamburg/ESO quasar HE 1113-0641 is found to be a quadruple gravitational lens, based on observations with the twin 6.5 m Magellan telescopes at the Las Campanas Observatory, and subsequently with the Hubble Space Telescope. The zS = 1.235 quasar appears in a cross configuration, with i' band magnitudes ranging from 18.0 to 18.8. Wit…
Ultra-Compact Dwarf Candidates Near the Lensing Galaxy in Abell S0740
Blakeslee, John P.; Barber DeGraaff, Regina
We analyze three-band imaging data of the giant elliptical galaxy ESO 325-G004 from the Hubble Space Telescope Advanced Camera for Surveys (ACS). This is the nearest known strongly lensing galaxy, and it resides in the center of the poor cluster Abell S0740 at redshift z = 0.034. Based on magnitude, color, and size selection criteria, we identify …
Radio Observations of the Hubble Deep Field-South Region. Iv. Optical Properties of the Faint Radio Population
Norris, Ray P.; Huynh, Minh T.; Jackson, Carole A. +1 more
The Australia Telescope Hubble Deep Field-South (ATHDF-S) survey of the Hubble Deep Field-South (HDF-S) reaches sensitivities of ~10 µJy at 1.4, 2.5, 5.2, and 8.7 GHz, making the ATHDF-S one of the deepest surveys ever performed with the Australia Telescope Compact Array (ATCA). Here, we present the optical identifications of the ATHDF-S rad…