Science Archives Publication System

NGC 2298: a globular cluster on its way to disruption

DOI: 10.1051/0004-6361:20066719 Bibcode: 2007A&A...467..107D

Pulone, L.; de Marchi, G.

We have studied the stellar main sequence (MS) of the globular cluster NGC 2298 using deep HST/ACS observations in the F606W and F814W bands covering an area of 3.4 arcmin × 3.4 arcmin around the cluster centre or about twice the cluster's half-mass radius. The colour-magnitude diagram that we derive in this way reveals a narrow and well defined M…

2007 • Astronomy and Astrophysics

eHST 30

The Faint End of the Luminosity Function in the Core of the Coma Cluster

DOI: 10.1086/509733 Bibcode: 2007AJ....133..177M

Kavelaars, J. J.; Gwyn, Stephen D. J.; Harris, William E. +4 more

We present optical measurements of the faint end of the luminosity function in the core of the Coma Cluster. Dwarf galaxies are detected down to a limiting magnitude of R~25.75 in images taken with the Hubble Space Telescope. This represents the faintest determination of the Coma luminosity function to date. With the assumption that errors due to …

2007 • The Astronomical Journal

eHST 30

Hubble Space Telescope observations of Comet 9P/Tempel 1 during the Deep Impact encounter

DOI: 10.1016/j.icarus.2006.07.027 Bibcode: 2007Icar..187..113F

Weaver, Harold A.; Feldman, Paul D.; A'Hearn, Michael F. +4 more

We report on the Hubble Space Telescope program to observe periodic Comet 9P/Tempel 1 in conjunction with NASA's Deep Impact Mission. Our objectives were to study the generation and evolution of the coma resulting from the impact and to obtain wide-band images of the visual outburst generated by the impact. Two observing campaigns utilizing a tota…

2007 • Icarus

eHST 30

Flow burst-induced Kelvin-Helmholtz waves in the terrestrial magnetotail

DOI: 10.1029/2007GL029459 Bibcode: 2007GeoRL..3410102V

Zhang, T. L.; Glassmeier, K. -H.; Lucek, E. +7 more

The Kelvin-Helmholtz instability (KHI) on the boundary of a flow channel in the Earth's plasma sheet is investigated using Cluster and Double Star TC1 data. It is shown that when Cluster moves into the flow channel the magnetometer measures strong oscillations of the magnetic field, that increase as the spacecraft move further into the flow channe…

2007 • Geophysical Research Letters

Cluster DoubleStar 30

A Low-Mass H₂ Component to the AU Microscopii Circumstellar Disk

DOI: 10.1086/521348 Bibcode: 2007ApJ...668.1174F

Redfield, Seth; Roberge, Aki; France, Kevin +2 more

We present a determination of the molecular gas mass in the AU Microscopii circumstellar disk. Direct detection of a gas component to the AU Mic disk has proven elusive, with upper limits derived from ultraviolet absorption line and submillimeter CO emission studies. Fluorescent emission lines of H₂, pumped by the O VI λ1032 resonance l…

2007 • The Astrophysical Journal

eHST 30

In-Orbit Focal Adjustment of the AKARI Telescope with Infrared Camera (IRC) Images

DOI: 10.1093/pasj/59.sp2.S423 Bibcode: 2007PASJ...59S.423K

Takagi, T.; Wada, T.; Onaka, T. +4 more

AKARI, currently in space, carries onboard a cryogenically cooled light-weight telescope with silicon carbide mirrors. The wavefront error of the AKARI telescope, obtained in laboratory measurements at 9 K, showed that the expected in-orbit imaging performance was diffraction-limited at a wavelength of 6.2 µm, slightly degraded from that exp…

2007 • Publications of the Astronomical Society of Japan

AKARI 30

Discovery of a Possible X-Ray Counterpart to HESS J1804-216

DOI: 10.1093/pasj/59.sp1.S209 Bibcode: 2007PASJ...59S.209B

Maeda, Yoshitomo; Kokubun, Motohide; Takahashi, Tadayuki +10 more

Suzaku deep observations have discovered two highly significant nonthermal X-ray sources, Suzaku J1804-2142 (Src 1) and Suzaku J1804-2140 (Src 2), positionally coincident with the unidentified TeV γ-ray source, HESS J1804-216. The X-ray sources are not time variable and show no counterpart in other wavebands, except for the TeV source. Src 1 is un…

2007 • Publications of the Astronomical Society of Japan

Suzaku 30

Structural parameters of Mayall II = G1 in M31

DOI: 10.1111/j.1365-2966.2007.11573.x Bibcode: 2007MNRAS.376.1621M

Wu, H.; Wu, J.; Chen, J. +8 more

Mayall II = G1 is one of the most luminous globular clusters (GCs) known in M31. New deep, high-resolution observations with the Advanced Camera for Surveys on the Hubble Space Telescope are used to provide accurate photometric data to the smallest radii yet. In particular, we present the precise variation of ellipticity and position angle, and of…

2007 • Monthly Notices of the Royal Astronomical Society

eHST 30

Oxygen temperature anisotropy and solar wind heating above coronal holes out to 5 R⊙

DOI: 10.1051/0004-6361:20077660 Bibcode: 2007A&A...476.1341T

Antonucci, E.; Telloni, D.; Dodero, M. A.

The purpose of the paper is to measure the degree of temperature anisotropy of the oxygen ions in the outer corona. The ratio of the Doppler dimmed O VI 1037-1032 line intensity as a function of the velocity of the fast solar wind, computed for typical values of coronal density, is consistent with the observed ratio, only when a significant temper…

2007 • Astronomy and Astrophysics

SOHO 30

Integral-Field Spectroscopy of the Post-Red Supergiant IRC +10420: Evidence for an Axisymmetric Wind

DOI: 10.1086/523692 Bibcode: 2007ApJ...671.2059D

Sahu, Kailash C.; Davies, Ben; Oudmaijer, René D.

We present NAOMI/OASIS adaptive-optics-assisted integral-field spectroscopy of the transitional massive hypergiant IRC +10420, an extreme mass-losing star apparently in the process of evolving from a red supergiant toward the Wolf-Rayet phase. To investigate the present-day mass-loss geometry of the star, we study the appearance of the line emissi…

2007 • The Astrophysical Journal

eHST 30