Search Publications
Metallicity-corrected Tip of the Red Giant Branch Distance to NGC 4258
Madore, Barry F.; Freedman, Wendy L.; Mager, Violet A.
We have determined the distance to NGC 4258 using observations made with the Hubble Space Telescope (HST) and the Wide Field, Advanced Camera for Surveys (ACS WFC). We apply a modified technique that fully accounts for metallicity effects on the use of the luminosity of the tip of the red giant branch (TRGB) to determine one of the most precise TR…
Ejecta, Dust, and Synchrotron Radiation in SNR B0540-69.3: A More Crab-Like Remnant than the Crab
Blair, William P.; Reynolds, Stephen P.; Points, Sean +10 more
We present near- and mid-infrared observations of the pulsar-wind nebula (PWN) SNR B0540-69.3 and its associated supernova remnant made with the Spitzer Space Telescope. We report detections of the PWN with all four IRAC bands, the 24 µm band of MIPS, and the Infrared Spectrograph (IRS). We find no evidence of IR emission from the X-ray/radi…
Magnetic Interaction: A Transequatorial Jet and Interconnecting Loops
Yang, Jiayan; Wang, Jingxiu; Shen, Yuandeng +2 more
We present, to our knowledge for the first time, a rare observation of direct magnetic interaction between a transequatorial jet and interconnecting loops (IL) in the southern hemisphere. The jet originated from a flare and appeared to move outward along open field lines, but it passed so close to the IL that its edge met with one of the IL ends. …
X-Ray-emitting Ejecta in Puppis A Observed with Suzaku
Petre, Robert; Hwang, Una; Flanagan, Kathryn A.
We report the detection and localization of X-ray-emitting ejecta in the middle-aged Galactic supernova remnant Puppis A using five observations with the Suzaku X-Ray Imaging Spectrometer to survey the eastern and middle portions of the remnant. A roughly 3' × 5', double-peaked region in the north center is found to be highly enriched in Si and ot…
Cosmic Evolution of Stellar Disk Truncations: From z ~ 1 to the Local Universe
Beckman, J. E.; Trujillo, I.; Azzollini, R.
We have conducted the largest systematic search so far for stellar disk truncations in disklike galaxies at intermediate redshift (z < 1.1), using the Great Observatories Origins Deep Survey-South (GOODS-S) data from the Hubble Space Telescope ACS. Focusing on type II galaxies (i.e., downbending profiles), we explore whether the position of the…
A Spectroscopic Orbit for Regulus
Rivinius, Th.; Štefl, S.; Baade, D. +8 more
We present a radial velocity study of the rapidly rotating B star Regulus that indicates the star is a single-lined spectroscopic binary. The orbital period (40.11 days) and probable semimajor axis (0.35 AU) are large enough that the system is not interacting at present. However, the mass function suggests that the secondary has a low mass (M…
AKARI Near-Infrared Spectroscopy: Detection of H2O and CO2 Ices toward Young Stellar Objects in the Large Magellanic Cloud
Onaka, Takashi; Ita, Yoshifusa; Sakon, Itsuki +4 more
We present the first results of AKARI Infrared Camera near-infrared spectroscopic survey of the Large Magellanic Cloud (LMC). We detected absorption features of the H2O ice 3.05 µm and the CO2 ice 4.27 µm stretching mode toward seven massive young stellar objects (YSOs). These samples are for the first time spectr…
Field Line Shrinkage in Flares Observed by the X-Ray Telescope on Hinode
Reeves, Katharine K.; Forbes, Terry G.; Seaton, Daniel B.
The X-Ray Telescope on Hinode has observed individual loops of plasma moving downward in a manner that is consistent with field line shrinkage in the aftermath of reconnection at higher altitudes. An on-disk B3.8 flare observed on 2007 May 2 has loops that clearly change in shape from cusp-shaped to more rounded. In addition, bright loops are obse…
Chandra Observations of the Pulsar B1929+10 and Its Environment
Garmire, G. P.; Pavlov, G. G.; Misanovic, Z.
We report on two Chandra observations of the 3 Myr old pulsar B1929+10, which reveal a faint compact (~9'' × 5'') nebula elongated in the direction perpendicular to the pulsar's proper motion, two patchy wings, and a possible short (~3'') jet emerging from the pulsar. In addition, we detect a tail extending up to a…
A Radio through X-Ray Study of the Jet/Companion-Galaxy Interaction in 3C 321
Lee, Julia C.; Kraft, Ralph P.; Birkinshaw, Mark +6 more
We present a multiwavelength study of the nucleus, environment, jets, and hot spots of the nearby FR II radio galaxy 3C 321, using new and archival data from MERLIN, the VLA, Spitzer, HST, and Chandra. An initially collimated radio jet extends northwest from the nucleus of its host galaxy and produces a compact knot of radio emission adjacent (in …