Search Publications
X-ray-Underluminous Active Galactic Nuclei Relative to Broad Emission Lines in Ultraluminous Infrared Galaxies
Imanishi, Masatoshi; Terashima, Yuichi
We present X-ray spectra of four ultraluminous infrared galaxies (ULIRGs) with detectable broad near-infrared emission lines produced by active galactic nuclei (AGNs): Mrk 463, PKS 1345+12, IRAS 05189-2524, and IRAS 07598+6508. With the exception of IRAS 07598+6508, high-quality X-ray spectra obtained with XMM or Chandra show modest (30-340 eV) eq…
Revealing the Young Starburst in Haro 3 with Radio and Infrared Imaging
Kobulnicky, Henry A.; Johnson, Kelsey E.; Indebetouw, Rémy +1 more
The Wolf-Rayet galaxy Haro 3 (Mrk 35, NGC 3353) was observed at the near-IR and radio wavelengths as part of an ongoing program to study the earliest stages of starbursts. These observations confirm that the current episode of star formation is dominated by a single region (region A). While there are knots of recent (~10 Myr) star formation outsid…
CNO Abundances in Metal-Rich Environments: Infrared Space Observatory Spectroscopy of Ionized Gas in M51
Skillman, Evan D.; Garnett, Donald R.; Edmunds, Michael G. +2 more
We present Infrared Space Observatory (ISO) Long Wavelength Spectrograph observations centered on the H II region CCM 10 in the spiral galaxy M51. We detect several emission lines in this spectrum, including [O I] 63 and 145 µm, [C II] 158 µm, [O III] 88 µm, and [N II] 122 µm, with a significant upper limit on [N III] 57 &m…
Did η Carinae's Weigelt Blobs Originate circa 1941?
Currie, Douglas G.; Hajian, Arsen R.; Dorland, Bryan N.
We report astrometric measurements of η Carinae's Weigelt blobs C and D (also known as speckle objects C and D) derived from observations with the Hubble Space Telescope Wide Field Planetary Camera 2. Using three epochs of data with a temporal baseline of 5.9 yr, we measure blob D's proper motion relative to the central star to be 4.4+/-1.4 mas yr…
The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda II
Da Costa, G. S.; Pritzl, Barton J.; Armandroff, Taft E. +1 more
We present the results of a variable star search in Andromeda II, a dwarf spheroidal galaxy companion to M31, using Hubble Space Telescope Wide Field Planetary Camera 2 observations. Seventy-three variables were found, one of which is an anomalous Cepheid while the others are RR Lyrae stars. The anomalous Cepheid has properties consistent with tho…
Markarian 1239: A Highly Polarized Narrow-Line Seyfert 1 Galaxy with a Steep X-Ray Spectrum and Strong Ne IX Emission
Komossa, S.; Grupe, D.; Mathur, S.
We report the results of an XMM-Newton observation of the narrow-line Seyfert 1 galaxy Mrk 1239. This optically highly polarized AGN has one of the steepest X-ray spectra found in AGNs, with αX=+3.0 based on ROSAT PSPC data. The XMM-Newton EPIC pn and MOS data confirm this steep X-ray spectrum. The pn data are best fitted by a power law…
Detecting Outflows from Cataclysmic Variables in the Optical
Honeycutt, R. K.; Kafka, S.
Cataclysmic variables (CVs) often show evidence of bipolar winds that carry away mass and angular momentum, likely affecting the evolution of the system. For the most part, it has only been possible to study such winds by means of the P Cygni profiles seen in space-UV resonance lines. We demonstrate that optical P Cygni profiles in two He I lines …
Dust and Ionized Gas in Nine Nearby Early-Type Galaxies Imaged with the Hubble Space Telescope Advanced Camera for Surveys
Ford, H. C.; Menanteau, F.; Illingworth, G. D. +6 more
We present V and I continuum images and Hα+[N II] maps of nine early-type galaxies observed with the Wide Field Channel of the Advanced Camera for Surveys on the Hubble Space Telescope. Dust and ionized gas are detected in all galaxies. The optical nebulae are primarily concentrated on the nuclei and extend out to radii of a few hundred parsecs in…
Optical Spectroscopy of K-Selected Extremely Red Galaxies
Soifer, B. T.; Yan, Lin; Thompson, David
We have obtained spectroscopic redshifts for 24 sources from a sample of bright, K-selected extremely red objects (EROs) using the Keck I Telescope. These EROs have high-resolution morphologies from the Hubble Space Telescope and were selected with a median Ks magnitude of 18.7 and F814W-Ks>4 mag (Yan & Thompson 2003).…
Hubble Space Telescope NICMOS Variability Study of Massive Stars in the Young Dense Galactic Starburst NGC 3603
Bergeron, E.; Moffat, A. F. J.; Marchenko, S. V. +4 more
We have used the relatively long data string of the 1997-1999 NICMOS focus tests on NGC 3603 to extract ~J-band light curves for several hundred stars in the cluster core. Given the relatively modest photometric precision [σ(J)>=0.05 mag], we were able to isolate only a half-dozen variable candidates with peak-to-valley amplitudes above ~0.2 ma…