Search Publications
Far-Infrared Properties of Blue Compact Dwarf Galaxies Observed with AKARI/Far-Infrared Surveyor (FIS)
Onaka, Takashi; Kaneda, Hidehiro; Suzuki, Toyoaki +1 more
We report on the basic far-infrared (FIR) properties of eight blue compact dwarf galaxies (BCDs) observed by AKARI. We have measured the fluxes at the four FIS bands (wavelengths of 65 µm, 90 µm, 140 µm, and 160 µm). Based on these fluxes, we have estimated basic quantities of dust: dust temperature, dust mass, and total FI…
A Transient Black Hole Low-Mass X-Ray Binary Candidate in Centaurus A
Hardcastle, M. J.; Croston, J. H.; Birkinshaw, M. +14 more
We report the discovery of a bright transient X-ray source, CXOU J132518.2-430304, toward Centaurus A (Cen A) using six new Chandra X-Ray Observatory observations in 2007 March-May. Between 2003 and 2007, its flux has increased by a factor of >770. The source is likely a low-mass X-ray binary in Cen A with unabsorbed 0.3-10 keV band luminositie…
Wolf-Rayet stars in M33 - II. Optical spectroscopy of emission-line stars in giant HII regions
Drissen, Laurent; Úbeda, Leonardo; Crowther, Paul A. +1 more
We present optical spectra of 14 emission-line stars in M33's giant HII regions NGC 592,595 and 604: five of them are known Wolf-Rayet (WR) stars, for which we present a better quality spectrogram, eight are WR candidates based on narrow-band imagery and one is a serendipitous discovery. Spectroscopy confirms the power of interference filter image…
Can We Constrain Solar Interior Physics by Studying the Gravity-Mode Asymptotic Signature?
García, R. A.; Mathur, S.; Ballot, J.
Gravity modes are the best probes to infer the properties of the solar radiative zone, which represents 98% of the Sun's total mass. It is usually assumed that high-frequency g modes give information about the structure of the solar interior whereas low-frequency g modes are more sensitive to the solar dynamics (the internal rotation). In this wor…
The Nature of the Ultraluminous Oxygen-Rich Supernova Remnant in NGC 4449
Milisavljevic, Dan; Fesen, Robert A.
Optical images and spectra, both ground based and taken by Hubble Space Telescope (HST), of the young, luminous O-rich supernova remnant in the irregular galaxy NGC 4449 are presented. HST images of the remnant and its local region were obtained with the ACS/WFC using filters F435W, F555W, F814W (B, V, and I, respectively), F502N ([O III]), F658N …
2006 December 17 Long Duration Flare Observed with the Hinode EUV Imaging Spectrometer
Harra, Louise K.; Doschek, George A.; Hara, Hirohisa +5 more
A GOES C-class long-duration flare that occurred near the west limb on 2006 December 17 was observed with the Hinode EUV Imaging Spectrometer (EIS) in raster-scan observations. Cusp-shaped arcades are prominent in the spectroheliogram of the CaXVII emission line at 192.86Å. Spatial relationships between hot flare loops with a cusp apex and cool po…
Luminosity-colour relations for thin-disc main-sequence stars
Cabrera-Lavers, A.; Bilir, S.; Yaz, E. +3 more
In this study we present the absolute magnitude calibrations of thin-disc main-sequence stars in the optical , and in the near-infrared . Thin-disc stars are identified by means of Padova isochrones, and absolute magnitudes for the sample are evaluated via the newly reduced Hipparcos data. The obtained calibrations cover a large range of spectral …
The massive binary HD 152218 revisited: A new colliding wind system in NGC 6231
Gosset, E.; Nazé, Y.; Rauw, G. +2 more
We present the results of an optical and X-ray monitoring campaign on the short-period massive SB2 binary HD 152218. Combining our HiRes spectroscopic data with previous observations, we unveil the contradictions between the published orbital solutions. In particular, we solve the aliasing on the period and derive a value close to 5.604 d. Our ecc…
The plasma filling factor of coronal bright points. Coronal bright points
Dere, K. P.
Aims: We determine the volumetric plasma filling factor of coronal bright points.
Methods: Rastered spectra of the regions of the quiet Sun were recorded by the Extreme ultraviolet Imaging Spectrometer (EIS) during operations with the Hinode satellite. Calibrated intensities of Fe XII lines were obtained and images of the quiet corona were con…
Nuclear activity in nearby galaxies. Mid-infrared imaging with the VLT
Pantin, E.; Siebenmorgen, R.; Moorwood, A. +7 more
Aims: Dust enshrouded activity can be studied ideally by mid-infrared (MIR) observations. To explore the active galactic nuclei (AGN) versus star forming origin of the nuclear MIR emission of galaxies, observations of high spatial resolution are required. We report on 11.3 µm observations with VISIR at the VLT, which reach 0.35'' spatial res…