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Post Info TOPIC: IGRJ17361-4441
Blobrana


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NGC 6388
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NGC 6388 (also ESO 279-SC2 and GCl 70) is a magnitude +6.8 globular star cluster located 32,300 light-years away in the constellation Scorpius.

The cluster was was discovered by Scottish astronomer James Dunlop using a homemade 9-foot 22.86 cm (9 inch) f/12 speculum Newtonian reflector at Paramatta, New South Wales, Australia, on the 13th May 1826.

Right Ascension 17h 36m 17.0s, Declination -44° 44' 04"



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Blobrana


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Title: X-ray Binaries in the Ultrahigh Encounter Rate Globular Cluster NGC 6388
Authors: J. Edward Maxwell, Phyllis M. Lugger, Haldan N. Cohn, Craig O. Heinke, Jonathan E. Grindlay, Sonia A. Budac, Gordon A. Drukier, Charles D. Bailyn

We report the results of a joint Chandra-HST study of the X-ray binary population in the massive, high-density globular cluster NGC 6388. NGC 6388 has one of the highest predicted X-ray binary production rate of any Galactic cluster. We detected a large population of 61 Chandra sources within the half-mass radius with L_X > 5 x 10^{30} \ergs. From the X-ray colours, luminosities, (lack of) variability, and spectral fitting, we identify five as likely quiescent low-mass X-ray binaries. Due to the extremely crowded nature of the core of NGC 6388, finding optical identifications to Chandra sources is challenging. We have identified four blue, optically variable counterparts to spectrally hard X-ray sources, evidence that these are bright cataclysmic variables (CVs). One showed variability of 2 magnitudes in V, indicative of a dwarf nova eruption. One other likely CV is identified by its X-ray spectrum (partial covering with high N_H) and strong variability, making five likely CVs identified in this cluster. The relatively bright optical magnitudes of these sources put them in the same class as CV1 in M15 and the brightest CVs in 47 Tuc.

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Blobrana


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IGRJ17361-4441
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Title: The XMM-Newton Slew view of IGRJ17361-4441: a transient in the globular cluster NGC 6388
Authors: A. A. Nucita, F. De Paolis, R. Saxton, A. M. Read

IGRJ17361-4441 is a hard transient recently observed by the INTEGRAL satellite. The source, close to the center of gravity of the globular cluster NGC 6388, quickly became the target of follow-up observations conducted by the Chandra, Swift/XRT and RXTE observatories. Here, we concentrate in particular on a set of observations conducted by the XMM-Newton satellite during two slews, in order to get the spectral information of the source and search for spectral variations. The spectral parameters determined by the recent XMM-Newton slew observations were compared to the previously known results. The maximum unabsorbed X-ray flux in the 0.5-10 keV band as detected by the XMM-Newton slew observations is \simeq 4.5 x 10^{-11} erg cm^{-2} s^{-1}, i.e. consistent with that observed by the Swift/XRT satellite 15 days earlier. The spectrum seems to be marginally consistent (\Gamma\simeq 0.93-1.63) with that derived from the previous high energy observation.

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