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The first source counts at 18 µm from the AKARI NEP Survey
Im, M.; Lee, H. M.; Serjeant, S. +9 more
We present the first galaxy counts at 18 µm using the Japanese AKARI satellite's survey at the North Ecliptic Pole (NEP), produced from the images from the NEP-Deep and NEP-Wide surveys covering 0.6 and 5.8 deg2, respectively. We describe a procedure using a point source filtering algorithm to remove background structure and a min…
Constraints on Two Active Galactic Nuclei in the Merger Remnant COSMOS J100043.15+020637.2
Comerford, J. M.; Wrobel, J. M.; Middelberg, E.
COSMOS J100043.15+020637.2 is a merger remnant at z = 0.36 with two optical nuclei, NW and SE, offset by 500 mas (2.5 kpc). Prior studies suggest two competing scenarios for these nuclei: (1) SE is an active galactic nucleus (AGN) lost from NW due to a gravitational-wave recoil. (2) NW and SE each contain an AGN, signaling a gravitational-slingsho…
Particle deposition on the saturnian satellites from ephemeral cryovolcanism on Enceladus
Showman, Adam P.; Hirata, Naoyuki; Miyamoto, Hideaki
The geologically active south pole of Enceladus generates a plume of micron-sized particles, which likely form Saturn's tenuous E-ring extending from the orbit of Mimas to Titan. Interactions between these particles and satellites have been suggested, though only as very thin surficial phenomena. We scrutinize high-resolution images with a newly d…
A photodissociation region study of NGC 4038
Barlow, M. J.; Bell, T. A.; Viti, S. +3 more
We present a model of the photodissociation regions of NGC 4038, which is part of the Antennae galaxies. We have considered one-dimensional slabs of uniform density, all having a maximum AV = 10 mag, interacting with plane-parallel radiation. The density range in our simulations spans four orders of magnitude (100 ≤ n ≤ 106 c…
Gravity waves in Titan's lower stratosphere from Huygens probe in situ temperature measurements
Young, Leslie A.; Lorenz, Ralph D.; Ferri, Francesca
The Huygens probe recorded atmospheric temperatures during its parachute descent through the atmosphere of Titan. A careful analysis of these data reveals for the first time spectacular but hitherto-unreported small-scale variations in stratospheric temperatures that we interpret as gravity waves, consistent with detection of such waves at higher …
The X-ray properties of the cometary blue compact dwarf galaxies Mrk 59 and Mrk 71
Bauer, F. E.; Thuan, T. X.; Izotov, Y. I.
We present XMM-Newton and Chandra observations of two low-metallicity cometary blue compact dwarf (BCD) galaxies, Mrk 59 and Mrk 71. The first BCD, Mrk 59, contains two ultraluminous X-ray sources (ULXs), IXO 72 and IXO 73, both associated with bright massive stars and H II complexes, as well as one fainter extended source associated with a massiv…
A comparison between VEGA 1, 2 and Giotto flybys of comet 1P/Halley: implications for Rosetta
Glassmeier, K. -H.; Volwerk, M.; Richter, I. +4 more
Three flybys of comet 1P/Halley, by VEGA 1, 2 and Giotto, are investigated with respect to the occurrence of mirror mode waves in the cometosheath and field line draping in the magnetic pile-up region around the nucleus. The time interval covered by these flybys is approximately 8 days, which is also the approximate length of an orbit or flyby of …
A Seyfert-2-like Spectrum in the High-mass X-Ray Binary Microquasar V4641 Sgr
Miller, Jon M.; Reynolds, M. T.; Maitra, Dipankar +1 more
We present an analysis of three archival Chandra observations of the black hole V4641 Sgr, performed during a decline into quiescence. The last two observations in the sequence can be modeled with a simple power law. The first spectrum, however, is remarkably similar to spectra observed in Seyfert-2 active galactic nuclei, which arise through a co…
Extended warm gas in the ULIRG Mrk273: Galactic outflows and tidal debris
Veilleux, S.; Rupke, D. S. N.; Sparks, W. B. +6 more
We present new HST/ACS medium- and narrow-band images and optical Isaac Newton Telescope long-slit spectra of the merging system Mrk273. The HST observations sample the [OIII]λλ4959,5007 emission from the galaxy and the nearby continuum. These data were taken as a part of a larger study of ultraluminous infrared galaxies (ULIRGs) with the aim of i…
HESS J1818-154, a new composite supernova remnant discovered in TeV gamma rays and X-rays
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +217 more
Composite supernova remnants (SNRs) constitute a small subclass of the remnants of massive stellar explosions where non-thermal radiation is observed from both the expanding shell-like shock front and from a pulsar wind nebula (PWN) located inside of the SNR. These systems represent a unique evolutionary phase of SNRs where observations in the rad…