Search Publications
A New Approach to the Study of Stellar Populations in Early-Type Galaxies: K-Band Spectral Indices and an Application to the Fornax Cluster
Kuntschner, Harald; Lyubenova, Mariya; Silva, David R.
The strong spectral features near 2.2 µm in early-type galaxies remain relatively unexplored. Yet, they open a tightly focused window on the coolest giant stars in these galaxies—a window that can be used to explore both age and metallicity effects. Here, new measurements of K-band spectral features are presented for 11 early-type galaxies i…
The Globular Cluster System of M60 (NGC 4649). II. Kinematics of the Globular Cluster System
Rey, Soo-Chang; Lee, Myung Gyoon; Hwang, Ho Seong +7 more
We present a kinematic analysis of the globular cluster (GC) system in the giant elliptical galaxy (gE) M60 in the Virgo Cluster, using a photometric and spectroscopic database of 121 GCs (83 blue and 38 red GCs). We have found that the M60 GC system shows a significant overall rotation. The rotation amplitude of the blue GCs is slightly smaller t…
The Variation of Relative Magnetic Helicity around Major Flares
Yang, Guo; Jing, Ju; Wang, Haimin +5 more
We have investigated the variation of magnetic helicity over a span of several days around the times of 11 X-class flares which occurred in seven active regions (NOAA 9672, 10030, 10314, 10486, 10564, 10696, and 10720) using the magnetograms taken by the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO). As a ma…
2 Years of INTEGRAL Monitoring of GRS 1915+105. I. Multiwavelength Coverage with INTEGRAL, RXTE, and the Ryle Radio Telescope
Belloni, T.; Rodriguez, J.; Cadolle Bel, M. +13 more
We report the results of simultaneous monitoring observations of the Galactic microquasar GRS 1915+105 with INTEGRAL and RXTE from 3 up to ~300 keV, and the Ryle Telescope at 15 GHz. We first identify the classes of variability in which GRS 1915+105 is found, and report some direct transitions between them. The accretion ejection connections are s…
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…