Science Archives Publication System

The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda VI

DOI: 10.1086/341823 Bibcode: 2002AJ....124.1464P

Pritzl, Barton J.; Armandroff, Taft E.; Da Costa, Gary S. +1 more

We have surveyed Andromeda VI, a dwarf spheroidal galaxy companion to M31, for variable stars by using F450W and F555W observations obtained with the Hubble Space Telescope. A total of 118 variables were found, including 111 RR Lyrae stars, six anomalous Cepheids, and one variable that we were unable to classify. We find that the Andromeda VI anom…

2002 • The Astronomical Journal

eHST 71

Determination of the Distance to M33 Based on the Tip of the Red Giant Branch and the Red Clump

DOI: 10.1086/324639 Bibcode: 2002AJ....123..244K

Sarajedini, Ata; Lee, Myung Gyoon; Geisler, Doug +2 more

We have determined the distance to M33 using the tip of the red giant branch (TRGB) and the red clump (RC), from the VI photometry of stars in 10 regions of M33 based on HST/WFPC2 images. The regions used in this study are located at R=2.6‧-17.8‧ from the center of M33. The distance modulus to M33 obtained in this study, for an adopted foreground …

2002 • The Astronomical Journal

eHST 71

The topology of a mixed-polarity potential field, and inferences for the heating of the quiet solar corona

DOI: 10.1023/A:1016295516408 Bibcode: 2002SoPh..207..223S

Title, Alan M.; Schrijver, Carolus J.

We study the statistical properties of the connectivity of the corona over the quiet Sun by analyzing the potential magnetic field above the central area of source planes sprinkled randomly with some 300 magnetic monopoles each. We find that the field is generally more complex than one might infer from a study of the field within the source plane …

2002 • Solar Physics

SOHO 71

Solar p-modes from 1979 days of the GOLF experiment

DOI: 10.1051/0004-6361:20021106 Bibcode: 2002A&A...394..285G

Grec, G.; Salabert, D.; Gelly, B. +5 more

With the GOLF instrument onboard the SoHO observatory, 1979 days of full-disc Doppler velocity observations have been compiled into a study of p-mode properties. We develop a multi-step iterative method (MSIM) algorithm to access all p-mode parameters while minimizing any perturbating effect or cross-talk between parameters during their determinat…

2002 • Astronomy and Astrophysics

SOHO 71

On the Column Density of AGN Outflows: The Case of NGC 5548

DOI: 10.1086/338113 Bibcode: 2002ApJ...566..699A

Korista, Kirk T.; Arav, Nahum; de Kool, Martijn

We reanalyze the Hubble Space Telescope high-resolution spectroscopic data of the intrinsic absorber in NGC 5548 and find that the C IV absorption column density is at least 4 times larger than previously determined. This increase arises from accounting for the kinematical nature of the absorber and from our conclusion that the outflow does not co…

2002 • The Astrophysical Journal

eHST 71

A Uniform Analysis of the Lyα Forest at z = 0-5. III. Hubble Space Telescope Faint Object Spectrograph Spectral Atlas

DOI: 10.1086/342489 Bibcode: 2002ApJS..140..143B

Bechtold, Jill; Tran, Kim-Vy; Dobrzycki, Adam +5 more

We analyzed the absorption line spectra of all quasars observed with the high-resolution gratings of the Faint Object Spectrograph on board the Hubble Space Telescope. We examined 788 spectra for 334 quasars and present line lists and identifications of absorption lines in the spectra of 271 of them. Analysis of the statistics of the Lyα and metal…

2002 • The Astrophysical Journal Supplement Series

eHST 70

The Microjansky Sky at 8.4 GHz

DOI: 10.1086/339308 Bibcode: 2002AJ....123.2402F

Fomalont, E. B.; Windhorst, R. A.; Richards, E. A. +2 more

We present the results from two deep radio integrations at 8.4 GHz using the Very Large Array. One of the fields, at 13^h, +43° (SA 13 field), has an rms noise level of 1.49 µJy and is the deepest radio image yet made. Thirty-four sources in a complete sample were detected above 7.5 µJy, and 25 are optically identified to a l…

2002 • The Astronomical Journal

eHST 70

Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. I. Method and a Preliminary Measurement for Fornax

DOI: 10.1086/344767 Bibcode: 2002AJ....124.3198P

Minniti, Dante; Mateo, Mario; Piatek, Slawomir +6 more

This article presents and discusses a method for measuring the proper motions of the Galactic dwarf spheroidal galaxies using images taken with the Hubble Space Telescope. The method involves fitting an effective point-spread function to the image of a star or quasi-stellar object to determine its centroid with an accuracy of about 0.005 pixels (0…

2002 • The Astronomical Journal

eHST 70

Molecular Gas and Nuclear Activity in Ultraluminous Infrared Galaxies with Double Nuclei

DOI: 10.1086/343867 Bibcode: 2002ApJ...580..749E

Sanders, D. B.; Surace, J. A.; Evans, A. S. +1 more

High-resolution CO(1-->0) observations of five ultraluminous infrared galaxies [ULIGs; L_IR(8-1000µm)>~10¹² L_solar] with double nuclei are analyzed. These sources constitute a complete subset of local ULIGs expected to be in an intermediate stage of merging and are selected to have projected nuclear sepa…

2002 • The Astrophysical Journal

eHST 70

Faint stars in the Ursa Minor dwarf spheroidal galaxy: implications for the low-mass stellar initial mass function at high redshift

DOI: 10.1016/S1384-1076(02)00156-2 Bibcode: 2002NewA....7..395W

Wyse, Rosemary F. G.; Gilmore, Gerard; Gallagher, John S., III +4 more

The stellar initial mass function at high redshift is an important defining property of the first stellar systems to form and may also play a role in various dark matter problems. We here determine the faint stellar luminosity function in an apparently dark-matter-dominated external galaxy in which the stars formed at high redshift. The Ursa Minor…

2002 • New Astronomy

eHST 70