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Resolved nuclear CO(1-0) emission in APM 08279+5255: gravitational lensing by a naked cusp?
Lewis, Geraint F.; Carilli, Chris; Papadopoulos, Padeli +1 more
The ultraluminous broad absorption line quasar APM 08279+5255 is one of the most luminous systems known. Here, we present an analysis of its nuclear emission. Its extended distribution suggests that the gravitational lens in this system is highly elliptical, probably a highly inclined disc. The quasar core, however, lies in the vicinity of a naked…
Toward the Secondary Bar: Gas Morphology and Dynamics in NGC 4303
Schinnerer, Eva; Scoville, Nick; Moustakas, Leonidas A. +1 more
We report on the molecular gas properties in the central kiloparsec of the almost face-on double-barred galaxy NGC 4303 (M61), using the 12CO 1-0 line emission observed with the Owens Valley Radio Observatory (OVRO) millimeter interferometer. The bulk of the molecular line emission comes from two straight gas lanes that run north-south …
Modeling the Hubble Space Telescope Ultraviolet and Optical Spectrum of Spot 1 on the Circumstellar Ring of SN 1987A
Filippenko, Alexei V.; Zhekov, Svetozar A.; Pun, Chun S. J. +18 more
We report and interpret Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) long-slit observations of the optical and ultraviolet (1150-10270 Å) emission line spectra of the rapidly brightening spot 1 on the equatorial ring of SN 1987A between 1997 September and 1999 October (days 3869-4606 after outburst). The emission is cau…
Off-limb EUV line profiles and the search for wave activity in the low corona
Harrison, R. A.; Hood, A. W.; Pike, C. D.
Two extreme-ultraviolet (EUV) observations are used to examine the off-limb characteristics of emission line widths of the million K Mg X 625 Å line. To obtain sufficient statistical accuracy, the observations were made over long periods of time and a pixel summing technique is used. The observations are made above the western limb, for quiet coro…
Boron Abundances in B-Type Stars: A Test of Rotational Depletion during Main-Sequence Evolution
Lennon, D. J.; Keenan, F. P.; Lambert, David L. +4 more
Boron abundances have been derived for seven main-sequence B-type stars from Hubble Space Telescope STIS spectra around the B III λ2066 line. In two stars, boron appears to be undepleted with respect to the presumed initial abundance. In one star, boron is detectable but is clearly depleted. In the other four stars, boron is undetectable, implying…
The Eagle's EGGs: Fertile or sterile?
Andersen, M.; McCaughrean, M. J.
We present a deep, high spatial resolution (0.35 arcsec FWHM), near-infrared (1-2.5 mu m) imaging survey of the Eagle Nebula, M 16, made with the VLT, centred on the famous elephant trunks. We compare these data with the existing HST optical images to search for evidence of ongoing or recent star formation in the trunks, and in particular in the 7…
Wind variability of B supergiants. IV. A survey of IUE time-series data of 11 B0 to B3 stars
Massa, D.; Prinja, R. K.; Fullerton, A. W.
We present the most suitable data sets available in the International Ultraviolet Explorer (IUE) archive for the study of time-dependent stellar winds in early B supergiants. The UV line profile variability in 11 B0 to B3 stars is analysed, compared and discussed, based on 16 separate data sets comprising over 600 homogeneously reduced high-resolu…
Determination of the Distance to M33 Based on Single-Epoch I-Band Hubble Space Telescope Observations of Cepheids
Sarajedini, Ata; Lee, Myung Gyoon; Gieren, Wolfgang +2 more
We have determined the distance to M33 using single-epoch I-band observations of Cepheids based on Hubble Space Telescope (HST)/Wide Field Planetary Camera 2 (WFPC2) images of five fields in M33. Combining the HST I-band photometry and the periods determined from the ground-based observations (DIRECT) for 21 Cepheids with logP>0.8 in the sample…
Detection of a Super-Star Cluster as the Ionizing Source in the Low-Luminosity Active Galactic Nucleus NGC 4303
Leitherer, Claus; Colina, Luis; Mas-Hesse, J. Miguel +1 more
Hubble Space Telescope (HST) ultraviolet Space Telescope Imaging Spectrograph (STIS) imaging and spectroscopy of the low-luminosity active galactic nucleus (LLAGN) NGC 4303 have identified the previously detected UV-bright nucleus of this galaxy as a compact, massive, and luminous stellar cluster. The cluster with a size (FWHM) of 3.1 pc and an ul…
Discovery of narrow X-ray absorption features from the dipping low-mass X-ray binary X 1624-490 with XMM-Newton
Parmar, A. N.; Boirin, L.; Oosterbroek, T. +1 more
We report the discovery of narrow X-ray absorption features from the dipping low-mass X-ray binary X1624-490 during an XMM-Newton observation in 2001 February. The features are identified with the Kalpha absorption lines of Fe XXV and Fe XXVI and have energies of 6.72 +/- 0.03 keV and 7.00 +/- 0.02 keV and equivalent widths (EWs) of -7.5 +1.7…