Search Publications
Compact Star Clusters in Nearby Dwarf Irregular Galaxies
Elmegreen, Bruce G.; Hunter, Deidre A.; Billett, Olivia H.
Nearby dwarf irregular galaxies were searched for compact star clusters by using data from the Hubble Space Telescope archives. Eight of the 22 galaxies in our sample were found to host compact clusters of some type. Three of these have populous clusters, with MV<-9.5 at a fiducial age of 10 Myr, and the same three also have super-st…
WIYN Open Cluster Study. X. The K-Band Magnitude of the Red Clump as a Distance Indicator
Sarajedini, Ata; Grocholski, Aaron J.
In an effort to improve the utility of the helium-burning red clump luminosity as a distance indicator, we explore the sensitivity of the K-band red clump absolute magnitude [MK(RC)] to metallicity and age. We rely upon JK photometry for 14 open clusters and two globular clusters from the Second Incremental Data Release of the Two Micro…
Spiral Galaxies with HST/NICMOS. I. Nuclear Morphologies, Color Maps, and Distinct Nuclei
Stiavelli, Massimo; de Zeeuw, P. Tim; Carollo, C. Marcella +2 more
This is the first of two papers where we present the analysis of an HST/NICMOS2 near-infrared (NIR) snapshot survey in the F160W (H) filter for a sample of 78 spiral galaxies selected from the UGC and ESOLV catalogs. For 69 of these objects we provide nuclear color information derived by combining the H data either with additional NICMOS F110W (J)…
Deep Hubble Space Telescope WFPC2 Photometry of NGC 288. I. Binary Systems and Blue Stragglers
Fusi Pecci, Flavio; Rood, Robert T.; Messineo, Maria +2 more
We present the first results of a deep WFPC2 photometric survey of the loose galactic globular cluster NGC 288. The fraction of binary systems is estimated from the color distribution of objects near the main sequence (MS) with a method analogous to that introduced by Rubenstein & Bailyn. We have unequivocally detected a significant population…
New High Proper Motion Stars from the Digitized Sky Survey. I. Northern Stars with 0.5" yr-1<µ<2.0" yr-1 at Low Galactic Latitudes
Lépine, Sébastien; Rich, R. Michael; Shara, Michael M.
We have conducted a systematic search for high proper motion stars in the Digitized Sky Survey, in the area of the sky north of -2.8 degrees in declination and within 25 degrees of the Galactic plane. Using the SUPERBLINK software, a powerful automated blink comparator developed by us, we have identified 601 stars in the magnitude range 9<r<…
Knots in Nearby Planetary Nebulae
O'Dell, C. R.; Balick, B.; Hajian, A. R. +2 more
HST emission-line images of five of the arguably closest planetary nebulae have shown that there is a progression of characteristics of their knots. This progression begins with dark tangential structures showing no alignment with the central star and location near the main ionization front. At the end of the progression in the largest nebulae, th…
Hubble Space Telescope Evidence for an Intermediate-Mass Black Hole in the Globular Cluster M15. I. STIS Spectroscopy and WFPC2 Photometry
Gerssen, Joris; van der Marel, Roeland P.; Gebhardt, Karl +2 more
In this series of two papers, we describe a project with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) to measure the line-of-sight velocities of stars in the central few arcseconds of the dense globular cluster M15. The main goal of this project is to search for the possible presence of an intermediate-mass c…
Further Insights into the Structure of 30 Doradus from the Hubble Space Telescope Instruments
Walborn, Nolan R.; Barbá, Rodolfo H.; Maíz-Apellániz, Jesús
New observations with the Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2), combined with prior archival data, provide nearly complete coverage of the inner 30 Doradus Nebula in both nebular lines and continuum at 0.1" resolution. The developing windblown cavity surrounding the massive first-generation, central cluster and its interfac…
M31 Globular Clusters in the Hubble Space Telescope Archive. II. Structural Parameters
Huchra, John P.; Barmby, Pauline; Holland, Stephen
We analyze the structural parameters of the largest available sample of spatially resolved extragalactic globular clusters. The images of M31 GCs were found in a search of Hubble Space Telescope (HST) archival data, described in a companion paper. We measure the ellipticities and position angles of the clusters and conclude that the ellipticities …
Crossing the Yellow Void: Spatially Resolved Spectroscopy of the Post-Red Supergiant IRC +10420 and Its Circumstellar Ejecta
Smith, Nathan; Humphreys, Roberta M.; Davidson, Kris
IRC +10420 is one of the extreme hypergiant stars that define the empirical upper luminosity boundary in the H-R diagram. During their post-red supergiant evolution, these massive stars enter a temperature range (6000-9000 K) of increased dynamical instability, high mass loss, and increasing opacity, a semiforbidden region that de Jager and his co…