Search Publications
The Influence of Mass and Environment on the Evolution of Early-Type Galaxies
Lanzoni, Barbara; Jørgensen, Inger; di Serego Alighieri, Sperello
We report on a uniform comparative analysis of the fundamental parameters of early-type galaxies at z~1 down to MB<=-20, both in the field and in clusters. The changes in the M/LB ratio from z~1 to today are larger for lower mass galaxies in all environments, and are larger in the field than in clusters for galaxies with t…
The Spatial Distribution of Faint Fuzzy Star Clusters in NGC 5195
Hwang, Narae; Lee, Myung Gyoon
We present a study of a faint fuzzy star cluster system in the nearby SB0 galaxy NGC 5195 interacting with the famous spiral galaxy NGC 5194 (M51), based on HST ACS BVI mosaic images taken by the Hubble Heritage Team. We have found about 50 faint fuzzy star clusters around NGC 5195 that are larger than typical globular clusters with effective radi…
FUSE Spectroscopy of the White Dwarf in U Geminorum
Brammer, Gabriel; Long, Knox S.; Froning, Cynthia S.
Observations of U Gem with FUSE confirm that the WD is heated by the outburst and cools during quiescence. At the end of an outburst, the best uniform-temperature WD model fits to the data indicate a temperature of 41,000-47,000 K, while in midquiescence, the temperature is 28,000-31,000 K, depending on the gravity assumed for the WD. Photospheric…
Challenging the Carbon Star Dust Condensation Sequence: Anarchist C Stars
Speck, Angela K.; Corman, Adrian B.; Thompson, Grant D. +1 more
There have been several investigations of the evolution of the mid-infrared (IR) dust features in carbon star spectra based on IRAS LRS data, but these studies are somewhat contradictory. In order to understand these differences in interpretations and to develop an understanding of the carbon star dust sequence, we have reexamined 26 IRAS LRS spec…
Luminosity Function of Faint Globular Clusters in M87
Zepf, Stephen E.; Lauer, Tod R.; Waters, Christopher Z. +2 more
We present the luminosity function to very faint magnitudes for the globular clusters in M87, based on a 30 orbit Hubble Space Telescope (HST) WFPC2 imaging program. The very deep images and corresponding improved false source rejection allow us to probe the mass function further beyond the turnover than has been done before. We compare our lumino…
An Estimation of the Acoustic Cutoff Frequency of the Sun Based on the Properties of the Low-Degree Pseudomodes
Jiménez, A.
The acoustic cutoff frequency (νac) is an important atmospheric parameter whose estimation has in the past been based on the study of power spectra that have yielded a wide range of values between 5300 and 5700 µHz. The discovery of a solar signal well beyond the acoustic cutoff frequency (pseudomodes) might lead one to think that…
Variations in D/H and D/O from New Far Ultraviolet Spectroscopic Explorer Observations
Chayer, Pierre; Kruk, Jeffrey W.; Oliveira, Cristina M. +1 more
We use data obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) to determine the interstellar abundances of D I, N I, O I, Fe II, and H2 along the sight lines to WD 1034+001, BD +39 3226, and TD1 32709. Our main focus is on determining the D/H, N/H, O/H, and D/O ratios along these sight lines, with logN(H)>20.0, that prob…
Gamma Rays and the Evolving, Compact Structures of the 2003 October 28 X17 Flare
Schrijver, C. J.; Hudson, H. S.; Tarbell, T. D. +2 more
The X17 flare on 2003 October 28 was observed by high-resolution imaging or spectroscopic instruments on CORONAS, GOES, INTEGRAL, RHESSI, SOHO, and TRACE. These spacecraft observed the temporal evolution of the γ-ray positron-annihilation and nuclear de-excitation line spectra, imaged the hard X-ray bremsstrahlung and EUV and UV emission, and meas…
XMM-Newton Observes Cl J0152.7-1357: A Massive Galaxy Cluster Forming at Merger Crossroads at z=0.83
Priedhorsky, W.; Córdova, F. A.; Maughan, B. J. +3 more
We present an analysis of a 50 ks XMM-Newton observation of the merging galaxy cluster Cl J0152.7-1357 at z=0.83. In addition to the two main subclusters and an infalling group detected in an earlier Chandra observation of the system, XMM-Newton detects another group of galaxies possibly associated with the cluster. This group may be connected to …
XMM-Newton Observations of the Bipolar Planetary Nebulae NGC 2346 and NGC 7026
Guerrero, Martín A.; Chu, You-Hua; Gruendl, Robert A. +1 more
We have obtained X-ray observations of the bipolar planetary nebulae (PNe) NGC 2346 and NGC 7026 with XMM-Newton. These observations detected diffuse X-ray emission from NGC 7026 but not from NGC 2346. The X-ray emission from NGC 7026 appears to be confined within the bipolar lobes of the PN and has spectral properties suggesting a thermal plasma …