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X-Ray Line-emitting Objects in XMM-Newton Observations: The Tip of the Iceberg
Braito, V.; Caccianiga, A.; Severgnini, P. +2 more
We present preliminary results from a novel search for X-ray line-emitting objects (XLEOs) in XMM-Newton images. Three sources have been detected in a test-run analysis of 13 XMM-Newton observations. The three objects found are most likely extremely absorbed active galactic nuclei characterized by a column density NH~1024 cm<…
Dwarf Novae with Newly Determined Parallaxes: Model Analyses of VY Aquarii, RU Pegasi, and T Leonis
Sion, E. M.; Hamilton, R. T.
Using newly determined parallaxes for dwarf novae, we have derived outburst accretion rates for VY Aqr, RU Peg, and T Leo, and for T Leo during quiescence. The two short-period dwarf novae, VY Aqr and T Leo, show good agreement with optically thick steady-state accretion disks in outburst, whereas RU Peg shows a significant departure from a steady…
Spitzer Space Telescope View of Diffuse Near-Infrared Continuum Emission in the Galaxy
Lu, Nanyao
The Infrared Array Camera (IRAC) multiband images from the Spitzer Space Telescope First Look Survey of two 1deg×5' areas of diffuse interstellar medium (ISM) are used to study the near-infrared (NIR; 2-5 µm) continuum emission and its relation to the mid-infrared (6-10 µm) aromatic features in emission (AFEs). We…
Spitzer Space Telescope Observations of the Aftermath of Microlensing Event MACHO-LMC-5
Stern, Daniel; Kallivayalil, Nitya; Nguyen, Hien T. +3 more
We have carried out photometry of the microlensing event MACHO-LMC-5 with Spitzer Infrared Array Camera (IRAC) 10 years after the magnification of the LMC source star was recorded. This event is unique in the annals of gravitational microlensing: the lensing star itself has been observed using the Hubble Space Telescope (once with WFPC2 and twice …
Hot Interstellar Gas and Stellar Energy Feedback in the Antennae Galaxies
Guerrero, Martín A.; Chu, You-Hua; Gruendl, Robert A. +3 more
We have analyzed Chandra archival observations of the Antennae galaxies to study the distribution and physical properties of its hot interstellar gas. Eleven distinct diffuse X-ray emission regions are selected according to their underlying interstellar structures and star formation activity. The X-ray spectra of these regions are used to determin…
Coronal response of Bi-directional Jets
Doyle, J. G.; Madjarska, M. S.; Dammasch, I. E. +1 more
EUV bi-directional jets are a prominent class of phenomena characterizing the solar transition region. Using simultaneously obtained SUMER observations in the chromospheric Si ii 1251.16 Å and C i 1251.17 Å, transition region N v 1238.8 Å and coronal Mg x 625 Å lines we show an example of a bi-directional jet observed in the chromospheric and the …
Models for Solar Magnetic Loops. IV. On the Relation between Coronal and Footpoint Plasma in Active Region Loops
Landi, E.; Feldman, U.
In the present work we analyze several SUMER intensity maps of active region solar loops in order to compare the relative brightnesses of the footpoints and the coronal section of active region loops. We find that the former are barely distinguishable from the background emission of the active region, while the coronal emission of loops is confine…
Astrometric Control of the Inertiality of the Hipparcos Catalog
Bobylev, V. V.
Based on the most complete list of the results of an individual comparison of the proper motions for stars of various programs common to the Hipparcos catalog, each of which is an independent realization of the inertial reference frame with regard to stellar proper motions, we redetermined the vector omega of residual rotation of the ICRS system r…
Period-luminosity relation for M-type semiregular variables from Hipparcos parallaxes
Yeşilyaprak, C.; Aslan, Z.
We have studied the period-luminosity (P-L) relationships of oxygen-rich semiregular (SR) variables in several wavelength bands using Hipparcos parallaxes with an accuracy of better than 10 per cent. We have shown that there is a clear dependence on period of absolute magnitude in the U,B,V,R,IC,J,H,K,L,M,N, [12], [25], [60] and [100] b…
Discovery of high-amplitude X-ray variability in the Seyfert-LINER transition galaxy NGC7589
Watson, M. G.; Osborne, J. P.; Yuan, W. +3 more
We present the first result of a programme to search for large flux variations in the X-ray sources of the XMM Serendipitous Survey compared to previous ROSAT observations. An increase in X-ray flux by a factor >10 was discovered from the nucleus of the galaxy NGC7589 on a time-scale of less than 5yr. The 0.4-10keV XMM spectrum can be approxima…