Science Archives Publication System

The Aromatic Infrared Bands as seen by ISO-SWS: Probing the PAH model

DOI: 10.1051/0004-6361:20010515 Bibcode: 2001A&A...372..981V

Léger, A.; Moutou, C.; Giard, M. +6 more

We discuss the Aromatic Infrared Band (AIB) profiles observed by ISO-SWS towards a number of bright interstellar regions where dense molecular gas is illuminated by stellar radiation. Our sample spans a broad range of excitation conditions (exciting radiation fields with effective temperature, T_eff, ranging from 23 000 to 45 000 K). The SWS spect…

2001 • Astronomy and Astrophysics

ISO 155

The Asymmetric Nebula Surrounding the Extreme Red Supergiant VY Canis Majoris

DOI: 10.1086/318748 Bibcode: 2001AJ....121.1111S

Smith, Nathan; Gehrz, Robert D.; Humphreys, Roberta M. +3 more

We present HST/WFPC2 images plus ground-based infrared images and photometry of the very luminous OH/IR star VY Canis Majoris. Our WFPC2 data show a complex distribution of knots and filamentary arcs in the asymmetric reflection nebula around the obscured central star. The reflection arcs may result from multiple, asymmetric ejection episodes due …

2001 • The Astronomical Journal

eHST 154

Dusty Debris around Solar-Type Stars: Temporal Disk Evolution

DOI: 10.1086/321490 Bibcode: 2001ApJ...555..932S

Zuckerman, B.; Silverstone, M. D.; Becklin, E. E. +2 more

Using ISO-ISOPHOT, we carried out a survey of almost 150 stars to search for evidence of emission from dust orbiting young main-sequence stars, both in clusters and isolated systems. Over half of the detections are new examples of dusty stellar systems and demonstrate that such dust can be detected around numerous stars older than a few times 10

2001 • The Astrophysical Journal

ISO 154

The Origin of C IV Absorption Systems at Redshifts z < 1: Discovery of Extended C IV Envelopes around Galaxies

DOI: 10.1086/321537 Bibcode: 2001ApJ...556..158C

Chen, Hsiao-Wen; Lanzetta, Kenneth M.; Webb, John K.

We report the discovery of extended C IV gaseous envelopes around galaxies of a wide range of luminosity and morphological type. First, we show that C IV absorption systems are strongly clustered around galaxies on velocity scales of v<~250 km s^-1 and impact parameter scales of ρ<~100 h^-1 kpc, but not on larger velocity…

2001 • The Astrophysical Journal

eHST 153

Complete and Simultaneous Spectral Observations of the Black Hole X-Ray Nova XTE J1118+480

DOI: 10.1086/321449 Bibcode: 2001ApJ...555..477M

Garnavich, P. M.; Groot, P. J.; Miller, J. M. +13 more

The X-ray nova XTE J1118+480 suffers minimal extinction (b=62^deg) and therefore represents an outstanding opportunity for multiwavelength studies. Hynes et al. conducted the first such study, which was centered on 2000 April 8 using UKIRT, EUVE, HST, and RXTE. On 2000 April 18, the Chandra X-Ray Observatory obtained data coincident with…

2001 • The Astrophysical Journal

eHST 152

A Serendipitous Galaxy Cluster Survey with XMM: Expected Catalog Properties and Scientific Applications

DOI: 10.1086/318382 Bibcode: 2001ApJ...547..594R

Romer, A. Kathy; Viana, Pedro T. P.; Liddle, Andrew R. +1 more

This paper describes a serendipitous galaxy cluster survey that we plan to conduct with the XMM X-ray satellite. We have modeled the expected properties of such a survey for three different cosmological models, using an extended Press-Schechter formalism combined with a detailed characterization of the expected capabilities of the European Photon …

2001 • The Astrophysical Journal

XMM-Newton 151

Measuring cluster temperature profiles with XMM/EPIC

DOI: 10.1051/0004-6361:20000017 Bibcode: 2001A&A...365L..80A

Aghanim, N.; Arnaud, M.; Hughes, J. P. +3 more

Using the PV observation of A1795, we illustrate the capability of XMM-EPIC to measure cluster temperature profiles, a key ingredient for the determination of cluster mass profiles through the equation of hydrostatic equilibrium. We develop a methodology for spatially resolved spectroscopy of extended sources, adapted to XMM background and vignett…

2001 • Astronomy and Astrophysics

XMM-Newton 150

The Chandra Deep Survey of the Hubble Deep Field North Area. IV. An Ultradeep Image of the HDF-N

DOI: 10.1086/321135 Bibcode: 2001AJ....122....1B

Hornschemeier, A. E.; Alexander, D. M.; Brandt, W. N. +7 more

We present results from a 479.7 ks Chandra exposure of the Hubble Deep Field North (HDF-N) and its immediate vicinity. In this X-ray image, the deepest ever reported with a 0.5-2.0 keV flux limit of ~4.9×10^-17 ergs cm^-2 s^-1, four new HDF-N X-ray sources are detected, bringing the total number of such sources to 12.…

2001 • The Astronomical Journal

eHST 150

Solar Neutrino Emission Deduced from a Seismic Model

DOI: 10.1086/321726 Bibcode: 2001ApJ...555L..69T

Kosovichev, A. G.; Christensen-Dalsgaard, J.; García, R. A. +10 more

Three helioseismic instruments on the Solar and Heliospheric Observatory have observed the Sun almost continuously since early 1996. This has led to detailed study of the biases induced by the instruments that measure intensity or Doppler velocity variation. Photospheric turbulence hardly influences the tiny signature of conditions in the energy-g…

2001 • The Astrophysical Journal

SOHO 148

The Frequency of Binary Stars in the Core of 47 Tucanae

DOI: 10.1086/322353 Bibcode: 2001ApJ...559.1060A

Albrow, Michael D.; Sarajedini, Ata; Gilliland, Ronald L. +3 more

Differential time series photometry has been derived for 46,422 main-sequence stars in the core of 47 Tucanae. The observations consisted of near-continuous 160 s exposures alternating between the F555W and F814W filters for 8.3 days in 1999 July with the Wide Field Planetary Camera 2 on the Hubble Space Telescope. Using Fourier and other search m…

2001 • The Astrophysical Journal

eHST 148