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First detection of [N II] 205 µm absorption in interstellar gas. Herschel-HIFI observations towards W 31C, W 49N, W 51, and G34.3+0.1
Menten, K. M.; Falgarone, E.; Levrier, F. +8 more
We present high resolution [N ii] 205 µm (3P1 - 3P0) spectra obtained with Herschel-HIFI towards a small sample of far-infrared bright star forming regions in the Galactic plane: W 31C (G10.6-0.4), W 49N (G43.2-0.1), W 51 (G49.5-0.4), and G34.3+0.1. All sources display an emission line profile asso…
Super-Eddington Accretion in the Ultraluminous X-Ray Source NGC 1313 X-2: An Ephemeral Feast
Weng, Shan-Shan; Zhao, Hai-Hui; Zhang, Shuang-Nan
We investigate the X-ray spectrum, variability, and the surrounding ionized bubble of NGC 1313 X-2 to explore the physics of super-Eddington accretion. Beyond the Eddington luminosity, the accretion disk of NGC 1313 X-2 is truncated at a large radius (~50 times the innermost stable circular orbit), and displays the similar evolution track with bot…
The distance to the Galactic center determined by OB stars
Branham, Richard L.
The OB stars are concentrated near the Galactic plane and should permit a determination of the distance to the Galactic center. van Leeuwen's new reduction of the Hipparcos catalog provides, after 824 Gould belt stars have been excluded, 6288 OB stars out to 1 kpc and Westin's compilation an additional 112 stars between 1 kpc and 3 kpc. The reduct…
Hubble Space Telescope Observations of the Nucleus of Comet C/2012 S1 (ISON)
Weaver, Harold A.; Toth, Imre; Lamy, Philippe L.
We report on the analysis of several sequences of broadband visible images of comet C/2012 S1 (ISON) taken with the Wide Field Camera 3 of the Hubble Space Telescope on 2013 April 10, May 8, October 9, and November 1 in an attempt to detect and characterize its nucleus. Whereas the overwhelming coma precluded the detection of the nucleus in the fi…
Ammonia observations in the LBV nebula G79.29+0.46. Discovery of a cold ring and some warm spots
Palau, Aina; Henkel, C.; Rizzo, J. R. +1 more
Context. The surroundings of luminous blue variable (LBV) stars are excellent laboratories to study the effects of their high UV radiation, powerful winds, and strong ejection events onto the surrounding gas and dust.
Aims: We aim at determining the physical parameters of the dense gas near G79.29+0.46, an LBV-candidate located at the centre …
Bursting emission from PSR B0611+22
Lorimer, D. R.; Seymour, A. D.; Ridley, J. P.
Over the past decade it has become apparent that a class of `bursting pulsars' exists with the discovery of PSR J1752+2359 and PSR J1938+2213. In these pulsars, a sharp increase in the emission is observed that then tends to systematically drop-off from pulse-to-pulse. In this paper we describe the discovery of such a relationship in high-sensitiv…
Comparison between Hinode/SOT and SDO/HMI, AIA data for the study of the solar flare trigger process
Kusano, Kanya; Bamba, Yumi; Iida, Yusuke +1 more
Understanding the mechanism that produces solar flares is important not only from the scientific point of view but also for improving space weather predictability. There are numerous observational and computational studies that have attempted to reveal the onset mechanism of solar flares. However, the underlying mechanism of flare onset remains el…
Solar Energetic Particle Events in Different Types of Solar Wind
Vourlidas, A.; Kahler, S. W.
We examine statistically some properties of 96 20 MeV gradual solar energetic proton (SEP) events as a function of three different types of solar wind (SW) as classified by Richardson and Cane. Gradual SEP (E > 10 MeV) events are produced in shocks driven by fast (V >~ 900 km s-1) and wide (W > 60°) coronal mass ejections (CMEs…
XMM-Newton and Chandra Observations of the Ejecta-dominated Mixed-morphology Galactic Supernova Remnant G352.7-0.1
Kargaltsev, Oleg; Pannuti, Thomas G.; Napier, Jared P. +1 more
We present a spatial and spectral X-ray analysis of the Galactic supernova remnant (SNR) G352.7-0.1 using archival data from observations made with the XMM-Newton X-ray Observatory and the Chandra X-ray Observatory. Prior X-ray observations of this SNR had revealed a thermal center-filled morphology that contrasts with a shell-like radio morpholog…
Suzaku Monitoring of Hard X-Ray Emission from η Carinae over a Single Binary Orbital Cycle
Hamaguchi, Kenji; Corcoran, Michael F.; Ishida, Manabu +6 more
The Suzaku X-ray observatory monitored the supermassive binary system η Carinae 10 times during the whole 5.5 yr orbital cycle between 2005 and 2011. This series of observations presents the first long-term monitoring of this enigmatic system in the extremely hard X-ray band between 15 and 40 keV. During most of the orbit, the 15-25 keV emission v…