Science Archives Publication System

Abell 2218: X-Ray Lensing, Merger, or Both?

DOI: 10.1086/310731 Bibcode: 1997ApJ...483L..17M

Markevitch, Maxim

Comparison of the high-resolution X-ray image of A2218 obtained with the ROSAT HRI with the optical HST image shows several interesting correlations. The X-ray emission within a 1' radius core is resolved into several components; the central dominant galaxy does not coincide with either of them or with the emission centroid. The major X-ray peak i…

1997 • The Astrophysical Journal

eHST 21

Pre-eclipse dips in the ultraviolet light curves of two eclipsing nova-like cataclysmic variables

DOI: 10.1093/mnras/290.2.L23 Bibcode: 1997MNRAS.290L..23M

Knigge, C.; Mason, K. O.; Drew, J. E.

Observations of the eclipsing nova-like variables UX UMa and RW Tri with the Hubble Space Telescope reveal substantial orbital modulations in their UV light. These modulations have a minimum about a quarter of an orbital cycle before eclipse. The modulation is deeper in RW Tri, which has the higher orbital inclination of the two binaries. The resi…

1997 • Monthly Notices of the Royal Astronomical Society

eHST 21

Bi-Dimensional Spectrography at HST-Like Spatial Resolution: [OIII] Kinematics and Ionization in the NLR of NGC 1068

DOI: 10.1023/A:1000573427252 Bibcode: 1997Ap&SS.248..167P

Binette, L.; Wilson, A. S.; Ferruit, P. +1 more

We present a study at HST-like spatial resolution of the gas kinematics in the innermost part of NGC 1068. This work is based on observations with the integral field spectrograph TIGER mounted on the CFH Telescope. We first derived the final spatial PSF of our data and checked its photometric integrity by comparison with two independent [OIII] HST…

1997 • Astrophysics and Space Science

eHST 21

Globular Cluster Photometry with the Hubble Space Telescope.VI.WF/PC-I Observations of the Stellar Populations in the Core of M13 (NGC 6205)

DOI: 10.1086/118285 Bibcode: 1997AJ....113..669C

Schneider, Donald P.; Yanny, Brian; Bahcall, John N. +2 more

We study the dense core of the globular cluster Messier 13 (NGC 6205) using pre-refurbishment Planetary Camera-I images obtained with the Hubble Space Telescope. Short exposures (60 s) through the F555W and F785LP filters (similar to Johnson V and I, respectively) have been used to obtain V and I photometry of 2877 stars brighter than V ~ 20 in a …

1997 • The Astronomical Journal

eHST 21

Signatures of Acoustic and Magnetic Waves in Solar and Stellar Coronae

DOI: 10.1086/304278 Bibcode: 1997ApJ...483..972W

Judge, Philip G.; Hansteen, Viggo H.; Wikstøl, Øivind

Time-dependent dynamical calculations of the radiating gas in solar coronal flux tubes are used to identify features of UV spectral-line profiles that can reveal the direction in which wave energy flows through the solar transition region. The profile features survive spatial and temporal averaging through nonlinear dependencies of line emission c…

1997 • The Astrophysical Journal

SOHO 21

Radial and azimuthal components of the heliospheric magnetic field: ulysses observations

DOI: 10.1016/S0273-1177(97)00480-8 Bibcode: 1997AdSpR..20...47S

Forsyth, R.; Balogh, A.; Burton, M. E. +2 more

Two invariants associated with the Parker model of the solar wind involve the radial, B_R, and azimuthal, B_T, components of the heliospheric magnetic field. These invariants have been investigated using Ulysses data obtained at high latitudes in both the north and south solar hemispheres. The magnetic flux invariant, r^2B_R, is essentially indepe…

1997 • Advances in Space Research

Ulysses 21

An Anomalous Ultraviolet Extension in NGC 6251

DOI: 10.1086/310839 Bibcode: 1997ApJ...486L..91C

Crane, P.; Vernet, J.

Deep U-band Faint Object Camera (FOC) images of the nuclear region of NGC 6251 have revealed a region of extended emission that is most probably radiation scattered from a continuum source in the nucleus. This radiation lies interior to a dust ring, is nearly perpendicular to the radio jet axis, and is seen primarily in the FOC U and B filters. Th…

1997 • The Astrophysical Journal

eHST 21

The relationship between UV and X-ray active region structures

DOI: 10.1023/A:1004951122397 Bibcode: 1997SoPh..175..541M

Matthews, S. A.; Harra-Murnion, L. K.

Yohkoh and the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO) jointly observed two brightenings in active region NOAA 7981 on 6 August 1996. Combining the UV data from CDS with information from the high time resolution coronal images obtained with the Soft X-ray Telescope (SXT) on Yohkoh, provides us with im…

1997 • Solar Physics

SOHO 21

The Star-Formation History in the Vicinity of NGC 1866 in the Large Magellanic Cloud

DOI: 10.1086/133888 Bibcode: 1997PASP..109..292S

Watson, A. M.; Holtzman, J. A.; Stapelfeldt, K. R. +15 more

To expand on the recent single WFPC2 field obtained in the vicinity of this cluster, we have measured the luminosity function in a one-third by one-half degree field in the LMC with the 40 inch telescope at Siding Spring Observator. Combining our results with recent 4-meter and WFPC2 observations, we examine the constraints on the star formation h…

1997 • Publications of the Astronomical Society of the Pacific

eHST 20

The Axis Ratio Distribution of Local and Distant Galaxies

DOI: 10.1086/118642 Bibcode: 1997AJ....114.2219O

Windhorst, Rogier A.; Burstein, David; Odewahn, Stephen C.

Surface photometry from 16 HST/WFPC2 fields in the I₈₁₄-band filter is used to derive the distribution of apparent axis ratios for galaxies in progressively fainter magnitude intervals for I₈₁₄≤25. We assess the systematic and accidental errors in ellipticity measurements as a function of image resolution and signal-to-noise …

1997 • The Astronomical Journal

eHST 20