xtej1720 - XMM-Newton
XMM-Newton Observation of XTE J1720-318
Events
- The X-Ray transient XTE J1720-318, was discovered by XTE on January 9 (Remillard et al., IAUC/ 5080).
- This bright transient was immediately approved by the XMM-Newton SOC for a ToO observation, and was observed as soon as it entered in the XMM-Newton visibility window.
- The observation was started on 2003-02-20T08:58:04Z under ObsId=0154750501 during XMM-Newton's revolution number 0586.
- EPIC pn was operated in Small Window mode, and MOS1 in timing mode.
- The pointing coordinates were RA = 17:19:59.8 and Dec = -31:44:46. The uncertainty in coordinates was reported as being about 20 arcseconds.
- A source was quickly identified in EPIC, ~15 arcseconds off in declination from the reported coordinates. The EPIC source position of the XTE J1720-318 X-ray counterpart was determined as RA = 17:19:59.0 and Dec -31:44:59. As stated below, this position is still subject to an uncertainty of about 4 arcseconds.
- Possible radio and infrared counterparts of XTE J1720-318 have been reported by Rupen et al. (IAUC/8054, RA=17:19:59.06 Dec=-31:44:59.7) and Kato et al. (IAUC/8056, RA=17:19:59.00 Dec=-31:45:01.2), respectively, in good agreement with the XMM-Newton position.
- The data presented here are based on a preliminary processing without the re-constituted XMM-Newton Attitude History File. Therefore, the positions quoted are subject to an uncertainty of 4 arcseconds.
Data
- The Observation Data File (ODF) is available here as 0154750501.tar.gz.
- The Pipeline Products are now also available in the ftp area. Details of the Pipeline process can be found here
Preview of XMM-Newton images (click on the images to see high resolution versions)
PN Small Window image
The XTE position of XTE J1720-318 and its reported uncertainty are marked by the circle.
Due to the extremely high brightness of the source, the mirror support construction of the XMM-Newton X-ray mirrors is reflected in the X-ray image as a number of radially oriented 'spokes'.
![](/documents/332006/1746892/pn_image.gif)
"Banana Plot" of the RGS2 spectrum showing up to the fourth dispersion order
![](/documents/332006/1746892/rgs_banana.gif)
Quick look analysis
RGS 1st order fluxed spectrum
The RGS first order spectrum of XTE J1720-318 showed a high count rate of 14 counts/sec. The decrease of the flux longward of 15 Angstroms is consistent with an Hydrogen column density of the order of 1022 cm-2. The observed flux in the range 1-2 keV is 1.1 10-9 erg/cm2/s.
![](/documents/332006/1746892/rgs_spectrum.gif)
EPIC spectra
The count rate was 588 counts/sec in EPIC-pn (core piled-up) and 346 counts/sec in EPIC-MOS (timing mode). The EPIC-pn spectrum has been extracted from an annulus between 16 and 28 arcsec from the source to avoid the piled-up core
![](/documents/332006/1746892/pn_mos.jpg)