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The Nature of Radio Continuum Emission in the Dwarf Starburst Galaxy NGC 625
Cannon, John M.; Skillman, Evan D.
We present new multifrequency radio continuum imaging of the dwarf starburst galaxy NGC 625 obtained with the Very Large Array. Data at 20, 6, and 3.6 cm reveal global continuum emission dominated by free-free emission, with only mild synchrotron components. Each of the major H II regions is detected; the individual spectral indices are thermal fo…
The Nature of SN 1961V
Chu, You-Hua; Gruendl, Robert A.; Stockdale, Christopher J. +3 more
The nature of SN 1961V has been uncertain. Its peculiar optical light curve and slow expansion velocity are similar to those of superoutbursts of luminous blue variables (LBVs), but its nonthermal radio spectral index and declining radio luminosity are consistent with decades-old supernovae (SNe). We have obtained Hubble Space Telescope STIS image…
An L0 dwarf companion in the brown dwarf desert, at 30 AU
Martín, E. L.; Ségransan, D.; Udry, S. +8 more
We present the discovery of an L0 companion to the nearby M1.5 dwarf G 239-25, at a projected distance of 31 AU. It is the faintest companion discovered so far in our adaptive optics survey of all known M dwarfs within 12 pc, and it lies at the stellar/substellar limit. Given the assumed age of the primary star, the companion is likely an extremel…
CIRPASS near-infrared integral-field spectroscopy of massive star clusters in the starburst galaxy NGC 1140
O'Connell, R. W.; Gallagher, J. S.; Smith, L. J. +6 more
We analyse near-infrared integral field spectroscopy of the central starburst region of NGC 1140, obtained at the Gemini-South telescope equipped with CIRPASS. Our ~1.45-1.67µm wavelength coverage includes the bright [FeII]λ 1.64-µm emission line, as well as high-order Brackett (hydrogen) lines. While strong [FeII] emission, thought to…
The location of the open-closed magnetic field line boundary in the dawn sector auroral ionosphere
Lester, M.; Rème, H.; Bosqued, J. +7 more
As a measure of the degree of coupling between the solar wind-magnetosphere-ionosphere systems, the rate at which the size of the polar cap (the region corresponding to ionospheric termini of open magnetic flux tubes) varies is of prime importance. However, a reliable technique by which the extent of the polar cap might be routinely monitored has …
Energetic neutral atoms from Jupiter measured with the Cassini magnetospheric imaging instrument: Time dependence and composition
Krimigis, S. M.; Mitchell, D. G.; Roelof, E. C. +2 more
During the Cassini spacecraft flyby of Jupiter in late 2000/early 2001, the Ion and Neutral Camera (INCA, one of three sensors that make up the Cassini Magnetospheric Imaging Instrument (MIMI)) obtained the first ever images of Jupiter's magnetosphere in energetic neutral atom (ENA) flux. These emissions are dominated by hydrogen atoms in the ener…
A Hubble Space Telescope Study of Star Formation in the Inner Resonance Ring of NGC 3081
Byrd, Gene G.; Freeman, Tarsh; Buta, Ronald J.
We present Hubble Space Telescope Wide Field Planetary Camera 2 images of the inner regions of NGC 3081, an absolute magnitude MB=-20.0 early-type barred spiral having four well-defined resonance rings: a nuclear ring, an inner ring, an outer R1 ring, and an outer R'2 pseudoring. Here we focus on a photo…
Late-type giant variables in NGC 6522, LMC and SMC. How do they differ?
Glass, I. S.; Schultheis, M.; Cioni, M. -R.
Complete samples of 2MASS stars in three fields of differing metallicities (and possibly differing age distributions) have been extracted and cross-correlated with MACHO and ISO data to determine their variability and mass-loss properties. In each MK histogram a fall-off in numbers is seen above the tip of the RGB. The luminosity of the…
Spectral Classification of Stars in A Supplement to the Bright Star Catalogue
Abt, Helmut A.
MK spectral types are given for about 584 stars in A Supplement to the Bright Star Catalogue. These are compared with Hipparcos parallaxes to check the reliability of those classifications. The estimated errors are +/-1.2 subtypes, and 10% of the luminosity classes may be wrong.
A Chandra View of the Normal S0 Galaxy NGC 1332. I. An Unbroken, Steep Power-Law Luminosity Function for the Low-Mass X-Ray Binary Population
Humphrey, Philip J.; Buote, David A.
Chandra ACIS -S3 observations of the nearby S0 galaxy NGC 1332 resolve much of the X-ray emission into 73 point sources, of which 37 lie within the D25 isophote. The remaining galaxy emission comprises hot, diffuse gas and unresolved sources and is discussed in two companion papers. The point-source X-ray luminosity function (XLF) shows…