Science Archives Publication System

Extragalactic globular clusters in the near infrared. I. A comparison between M87 and NGC 4478

DOI: 10.1051/0004-6361:20020831 Bibcode: 2002A&A...391..441K

Minniti, D.; Kissler-Patig, M.; Brodie, J. P.

We compare optical and near infrared colours of globular clusters in M87, the central giant elliptical in Virgo, and NGC 4478, an intermediate luminosity galaxy in Virgo, close in projection to M87. Combining V and I photometry obtained with the WFPC2 on HST and K_s photometry obtained with the NIRC on Keck 1, we find the broad range in colour and…

2002 • Astronomy and Astrophysics

eHST 42

The young intermediate-mass stellar object AFGL 490 - A disk surrounded by a cold envelope

DOI: 10.1051/0004-6361:20021160 Bibcode: 2002A&A...394..561S

Henning, Th.; van Dishoeck, E. F.; van der Tak, F. F. S. +2 more

AFGL 490 is a key target of the class of deeply embedded intermediate-mass young stellar objects in a transition stage to Herbig Be stars (L = 2.2-4.0 x 10³ L_sun ). In this paper, we present a comprehensive set of single-dish line data which characterize the envelope of the source. In addition, observations of CS J = 2->1 …

2002 • Astronomy and Astrophysics

ISO 42

On the Distance of Magellanic Clouds: First Overtone Cepheids

DOI: 10.1086/342211 Bibcode: 2002ApJ...574L..33B

Marconi, M.; Bono, G.; Caputo, F. +1 more

We present a detailed comparison between predicted and empirical PL_I,K relations and the Wesenheit function for Galactic and Magellanic Cloud (MC) first overtone (FO) Cepheids. We find that zero points predicted by Galactic Cepheid models based on a noncanonical (mild overshooting) mass-luminosity (ML) relation are in very good agreemen…

2002 • The Astrophysical Journal

Hipparcos 42

On the Observational Properties of He-burning Stars: Some Clues on the Tilt of the Horizontal Branch in Metal-rich Clusters

DOI: 10.1086/339428 Bibcode: 2002ApJ...569..975R

Piotto, G.; Cassisi, S.; Castellani, V. +2 more

We investigate the predicted color-magnitude distribution of metal-rich horizontal-branch (HB) stars, discussing selected theoretical models computed under various assumptions about the star metallicity and the efficiency of superadiabatic convection. We find that canonical zero-age horizontal branches with metallicity larger or of the order of Z=…

2002 • The Astrophysical Journal

eHST 42

Dissecting the Luminosity Function of the Coma Cluster of Galaxies Using Canada-France-Hawaii Telescope Wide-Field Images

DOI: 10.1086/339261 Bibcode: 2002ApJ...569..144A

Andreon, S.; Cuillandre, J. -C.

We determined the relative spatial density of the Coma Cluster galaxies, selected by luminosity and by central brightness, i.e., the luminosity function bivariate in central brightness. The Coma Cluster and control fields were imaged using the CFH12K (42^'×28^') and UH8K (28^'×28^') wide-field cameras at the…

2002 • The Astrophysical Journal

eHST 42

Discovery of Soft X-Ray Emission from Io, Europa, and the Io Plasma Torus

DOI: 10.1086/340434 Bibcode: 2002ApJ...572.1077E

Johnson, Robert E.; Weisskopf, Martin C.; Tennant, Allyn F. +13 more

We report the discovery of soft (0.25-2 keV) X-ray emission from the Galilean satellites Io and Europa, probably Ganymede, and from the Io Plasma Torus (IPT). Bombardment by energetic (greater than 10 keV) H, O, and S ions from the region of the IPT seems to be the likely source of the X-ray emission from the Galilean satellites. According to our …

2002 • The Astrophysical Journal

Ulysses 42

Discovery of Enhanced Germanium Abundances in Planetary Nebulae with the Far Ultraviolet Spectroscopic Explorer

DOI: 10.1086/344473 Bibcode: 2002ApJ...578L..55S

Dinerstein, Harriet L.; Sterling, N. C.; Bowers, Charles W.

We report the discovery of Ge III λ1088.46 in the planetary nebulae (PNe) SwSt 1, BD +30°3639, NGC 3132, and IC 4593, observed with the Far Ultraviolet Spectroscopic Explorer. This is the first astronomical detection of this line and the first measurement of Ge (Z=32) in PNe. We estimate Ge abundances using S and Fe as reference elements, for a ra…

2002 • The Astrophysical Journal

eHST 42

Lyman Break Galaxies and the Reionization of the Intergalactic Medium

DOI: 10.1086/340770 Bibcode: 2002ApJ...569L..65F

Papovich, Casey; Dickinson, Mark; Ferguson, Henry C.

Near-infrared observations of Lyman break galaxies at redshifts of z~3 are beginning to provide constraints on ages, star formation histories, dust content, metallicities, and stellar masses. At present, uncertainties of more than an order of magnitude are typical for many of these parameters. It is nonetheless interesting to ask what the stellar …

2002 • The Astrophysical Journal

eHST 42

Far-infrared emission from intracluster dust in Abell clusters

DOI: 10.1051/0004-6361:20011613 Bibcode: 2002A&A...383..367S

Lemke, D.; Klaas, U.; Mattila, K. +1 more

The ISOPHOT instrument aboard ISO has been used to observe extended FIR emission of six Abell clusters. Strip scanning measurements with crossing position angles centered on the clusters were carried out at 120 µ m and 180 µ m. The raw profiles of the I_{120 µ m}/I_{180 µ m} surface brightness ratio includin…

2002 • Astronomy and Astrophysics

ISO 42

The Nature of Ultraluminous X-Ray Sources in NGC 4565

DOI: 10.1086/341862 Bibcode: 2002ApJ...576..738W

Xia, X. Y.; Xue, S. J.; Mao, S. +2 more

We report the optical identifications of two X-ray-luminous point sources in the spiral galaxy NGC 4565 based on archive data of Chandra and the Hubble Space Telescope. The central X-ray point source, RX J1236.3+2559, is found to be the nucleus of NGC 4565 with an X-ray luminosity of L_X~4.3×10³⁹ ergs s^-1. We show t…

2002 • The Astrophysical Journal

eHST 42