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Probable intermediate-mass black holes in NGC 4559: XMM-Newton spectral and timing constraints
Cropper, Mark; Soria, Roberto; Wu, Kinwah +3 more
We have examined X-ray and optical observations of two ultraluminous X-ray sources, X7 and X10 in NGC 4559, using XMM-Newton, Chandra and the Hubble Space Telescope (HST). The ultraviolet/X-ray luminosity of X7 exceeds 2.1 × 1040 erg s-1 in the XMM-Newton observation, and that of X10 is > 1.3 × 1040 erg s-1…
Obscuration and Origin of Nuclear X-Ray Emission in FR I Radio Galaxies
Gliozzi, M.; Sambruna, R. M.; Donato, D.
We present X-ray observations of the nuclear region of 25 Fanaroff-Riley type I (FR I) radio galaxies from the 3CRR and B2 catalogs, using data from the Chandra and XMM-Newton archives. We find the presence of a X-ray central compact core (CCCX) in 13/25 sources; in 3/25 sources the detection of a CCCX is uncertain, while in the remaining 9/25 sou…
Field E+A Galaxies at Intermediate Redshifts (0.3 < z < 1)
Franx, Marijn; Kelson, Daniel D.; Illingworth, Garth D. +3 more
We select E+A candidates from a spectroscopic data set of ~800 field galaxies and measure the E+A fraction at 0.3<z<1 to be 2.7%+/-1.1%, a value lower than that in galaxy clusters at comparable redshifts (11%+/-3%). HST WFPC2 imaging for five of our six E+A's shows that they have a heterogeneous parent population: these E+A's span a range in…
Follow-Up Chandra Observations of Three Candidate Tidal Disruption Events
Komossa, S.; Halpern, J. P.; Gezari, S.
Large-amplitude, high-luminosity soft X-ray flares were detected by the ROSAT All-Sky Survey in several galaxies with no evidence of Seyfert activity in their ground-based optical spectra. These flares had the properties predicted for a tidal disruption of a star by a central supermassive black hole. We report Chandra observations of three of thes…
Coronal Shocks of November 1997 Revisited: The Cme Type II Timing Problem
Thompson, B. J.; Zhang, J.; Nitta, N. V. +1 more
We re-examine observations bearing on the origin of metric type II bursts for six impulsive solar events in November 1997. Previous analyses of these events indicated that the metric type IIs were due to flares (either blast waves or ejecta). Our point of departure was the study of Zhang et al. (2001) based on the Large Angle and Spectrometric Cor…
The Effects of Stratification on Oscillating Coronal Loops
Erdélyi, Robert; Mendoza-Briceño, César A.; Sigalotti, Leonardo Di G.
Recent observations by the Solar and Heliospheric Observatory (SOHO) and the Transition Region and Coronal Explorer (TRACE) have confirmed previous theoretical predictions that coronal loops may oscillate. These oscillations and their damping are of fundamental importance, because they can provide diagnostics of the coronal plasma. In the present …
Ultraviolet Light from Young Stars in GEMS Quasar Host Galaxies at 1.8<z<2.75
Heymans, C.; Wolf, C.; Barden, M. +14 more
We have performed Hubble Space Telescope imaging of a sample of 23 high-redshift (1.8<z<2.75) active galactic nuclei (AGNs), drawn from the COMBO-17 survey. The sample contains moderately luminous quasars (MB~-23). The data are part of the Galaxy Evolution from Morphologies and SEDs imaging survey that provides high-resolution opt…
Dust emission in early-type galaxies: The mid-infrared view
Madden, S. C.; Galliano, F.; Sauvage, M. +2 more
We present mid-infrared (MIR) maps for a sample of 18 early-type galaxies observed at 4.5, 6.7 and 15 µ m with the ISOCAM instrument on board the ISO satellite with a 6'' spatial resolution. We model the Spectral Energy Distribution (SED) of these galaxies using the stellar evolutionary synthesis model PÉGASE and we derive the MIR excess ove…
Molecular Gas at High Redshift: Jet-induced Star Formation?
Ekers, R. D.; Sadler, E. M.; Hunstead, R. W. +1 more
We present an alternative interpretation of the observations of BR 1202-0725 at z=4.695 and show that its properties are consistent with a relativistic jet issuing from the quasar core, propagating into the intergalactic medium, and triggering star formation along its path. Prompted by this finding, we reviewed all the z>3 objects detected in m…
Polycyclic Aromatic Hydrocarbon Emission in the 15-21 Micron Region
Allamandola, L. J.; Peeters, E.; Mattioda, A. L. +1 more
Observations from the Spitzer Space Telescope have drawn attention to spectroscopic structure longward of 15 µm that is associated with objects showing prominent unidentified infrared (UIR) bands in the mid-IR. If polycyclic aromatic hydrocarbons (PAHs) are indeed responsible for the UIR features, longer wavelength emission arising from out-…