Search Publications
Exploring the nuclear environment of the NLS1 galaxy Arakelian 564 with XMM-Newton RGS
Page, M. J.; Branduardi-Raymont, G.; Smith, R. A. N.
Aims: We present an accurate characterisation of the high-resolution X-ray spectrum of the Narrow Line Seyfert 1 galaxy Arakelian 564 and put it in to context with other objects of its type by making a detailed comparison of their spectra.
Methods: The data are taken from 5 observations with the XMM-Newton Reflection Grating Spectrometer and f…
The Structure of the DoAr 25 Circumstellar Disk
Wilner, D. J.; Andrews, Sean M.; Qi, Chunhua +1 more
We present high spatial resolution (lsim 0.3'' ≈ 40 AU) Submillimeter Array observations of the 865 µm continuum emission from the circumstellar disk around the young star DoAr 25. Despite its bright millimeter emission, this source exhibits only a comparatively small infrared excess and low accretion rate, suggesting that the material and s…
Discovery of a Bright Transient Ultraluminous X-Ray Source, Suzaku J1305-4931 in NGC4945
Isobe, Naoki; Gandhi, Poshak; Makishima, Kazuo +5 more
An X-ray source, Suzaku J1305-4931, was discovered in the south-west arm of a nearby Seyfert II galaxy, NGC4945, at 0.5-10keV flux of 2.2×10-12erg cm-2 s-1 during a Suzaku observation conducted on 2006 January 15-17. It was undetectable in a shorter observation on 2005 August 22--23, with an upper limit of 1.7×10
The Lack of Strong O-Line Excess in the Coma Cluster Outskirts from Suzaku
Miller, Eric D.; Bregman, Joel N.; Ohashi, Takaya +6 more
About half of the baryons in the local universe are thought to reside in the so-called warm-hot intergalactic medium (WHIM) at temperatures of 0.1-10 MK. Thermal soft excess emission in the spectrum of some cluster outskirts that contains O VII and/or O VIII emission lines is regarded as evidence of the WHIM, although the origin of the lines is co…
M dwarfs at large heliocentric distances
Lehnert, Matthew D.; Stanway, Elizabeth R.; Bremer, Malcolm N. +1 more
We present an analysis of the faint M star population seen as foreground contaminants in deep extragalactic surveys. We use space-based data to separate such stars from high-redshift galaxies in a publicly available data set, and consider the photometric properties of the resulting sample in the optical and infrared. The inferred distances place t…
Absolute dimensions and apsidal motion of the eccentric binary PT Velorum
Demircan, O.; Bakış, V.; Eker, Z. +1 more
High-resolution (λ/dλ ~ 41000) echelle spectra of the eccentric binary system PT Vel were analysed. Precise spectroscopic orbital elements of the system were obtained by means of cross-correlation technique. According to the solution of radial velocities with Hipparcos and All Sky Automated Survey-3 (ASAS-3) light curves, PT Vel consists of two ma…
Magnetic Twist of EUV Coronal Loops Well-traced in TRACE Images: Evidence for Magnetic Reconnection Origin of Coronal Loops?
Chae, Jongchul; Kwon, Ryun Young
The measurements of magnetic twist of EUV coronal loops for 14 loops are presented here. EUV coronal loops are thin, EUV-emitting structures of hot plasma tracing magnetic field lines in the corona. The constriction of plasma into a loop without dispersion may be explained if the magnetic field of the loop is twisted. On the basis of this idea, Ch…
Hubble Space Telescope Images of Red Mergers: How Dry Are They?
van Dokkum, Pieter G.; Whitaker, Katherine E.
Mergers between red galaxies are observed to be common in the nearby universe, and are thought to be the dominant mechanism by which massive galaxies grow their mass at late times. These "dry" mergers can be readily identified in very deep ground-based images, thanks to their extended low surface brightness tidal features. However, ground-based im…
Preliminary Orbit and Differential Photometry of the Nearby Flare Star CR Dra
Docobo, José A.; Tamazian, Vakhtang S.; Melikian, Norair D. +3 more
New speckle measurements with the 6 m telescope of the Special Astrophysical Observatory (Russia) and the first preliminary orbit of the nearby flare star CR Dra (=Gl 616.2; WDS 16171+5516; BLA 3) with a period of 4.04 yr and a semimajor axis of 0farcs148 are reported. The Hipparcos parallax of 48.36 ± 1.16 mas (distance 20.7 pc) leads to an unusu…
3C40 in Abell194: can tail radio galaxies exist in a quiescent cluster?
Hardcastle, M. J.; Sakelliou, Irini; Jetha, N. N.
The nearby cluster Abell194 hosts two luminous, distorted radio galaxies. Both reside within the cluster's core region, being separated in projection by only 100 kpc. It is often suggested that tailed radio galaxies such as these reside in clusters that are under formation and are accreting new material from their outskirts. In this paper, we stud…