INTEGRAL News archive for 2003


SPI detector #2 anomaly

10 December 2003 On saturday 6 in the morning the counting rate from detector 2 dropped to zero. The HK parameters showed that the problem is localized in the GeD preamplifier : the offset of the preamp has a non-nominal value. All the other parameters are correct and stable. We performed some recovery attempts with no success on Monday 8. Up to now the reason of the problem is unknown. We are doing our best to understand the problem and to propose some other recovery actions. The behaviour and performances of the other detectors are perfect.

Jean-Pierre Roques, SPI Team

Gamma Ray Burst GRB031203

05 December 2003 On December 3 at 22:01:28 UTC INTEGRAL finally imaged a Gamma-Ray Burst (GRB) in the field of view of the gamma-ray instruments. The last burst in the field of view was observed on the first of May, and before that time they were observed almost regularly each month. But the long wait for the new burst has certainly been worthwile: it is a long (30s), and bright (peak flux 1.2 photons cm-2 s-1) GRB. The burst was detected by IBAS and a position with an accuracy of 6 arc minutes was sent out within 10 s of its occurence (GCN 2459).

Follow-up observations were performed by XMM-Newton which detected two sources in the INTEGRAL uncertainty region (GCN 2464). Further optical observations revealed a new optical source consistent with one of the XMM-Newton sources. The optical properties of this source appear interesting: it is detected in the H- and K-band with a magnitude of 14.9 and 13.4 respectively (GCN 2466), while the I-band magnitude is > 23, and the J-band magnitude is 20.5 (GCN 2468). The large difference between the H- and K-band magnitudes and I- and J-band magnitudes is very unusual and can be explained in terms of irregular extinction or even by the fact that the GRB has its origin at very high redshifts (z ~10), although the last interpretation is possibly hard to reconcile with the high brightness of the afterglow, which is probably in the top 10% of all afterglows (GCNs 2468, 2469).

Once again this shows the high importance of GRB detections by INTEGRAL, and rapid follow-ups by XMM-Newton and optical telescopes.

ESA Brochure (BR-210)

04 December 2003 The International Gamma-Ray Astrophysics Laboratory - 1 Year in Orbit (PDF, 10.4 Mbytes)

The last cry of matter

27 November 2003 Black holes are truly black. When an object gets within a certain distance from a black hole, it will get swallowed forever with no chance to escape. That includes light, which means that black holes do not shine.

How do astronomers detect black holes if they are unable to see them? Well, to be precise, astronomers do not detect black holes. But they do detect the phenomena that can only be explained by the existence nearby of objects that match the description of black holes!

For the full story, see the ESA Portal (Feature of the week): The last cry of matter

The INTEGRAL Mission Extension

19 November 2003 At its 105th meeting held on 5-6 November 2003 the ESA Science Programme Committee (SPC) unanimously approved a 4-year rolling extension to INTEGRAL operations from 17 December 2004 until 16 December 2008.

Read more: The INTEGRAL Mission Extension

The INTEGRAL ISOC Newsletter #10 is on-line

14 November 2003 ISOC Newsletter #10

See also the previous issues of the ISOC Newsletter.

ESA's new view of the Milky Way - in gamma rays!

10 November 2003 ESA's gamma-ray observatory INTEGRAL is making excellent progress, mapping the Galaxy at key gamma-ray wavelengths. It is now poised to give astronomers their truest picture yet of recent changes in the Milky Way's chemical composition. At the same time, it has confirmed an 'antimatter' mystery at the centre of the Galaxy.

For more information, see the ESA Science News Release (SNR-23-2003):
ESA's new view of the Milky Way - in gamma rays!

INTEGRAL AO-2 General Programme approved.

04 November 2003 The INTEGRAL AO-2 General Programme, as approved by the Time Allocation Committee has been released today.

A&A Special Letters Edition on First science with INTEGRAL

29 October 2003 This Astronomy and Astrophysic Special Letters Issue features the INTEGRAL observatory. About one year after its successful launch, this series of 75 publications describe the mission, the various instruments and their performance, as well as first scientific results from the spacecraft, ranging from gamma-ray bursts to Galactic sources.

See:
The INTEGRAL Scientific Publications page
Astronomy and Astrophysics Special Letters Issue, Volume 411-1 (November III 2003)

ESA's INTEGRAL discovers hidden black holes

17 October 2003 INTEGRAL, ESA's powerful gamma-ray space telescope, has discovered what seems to be a new class of astronomical objects. These are binary systems, probably including a black hole or a neutron star, embedded in a thick cocoon of cold gas. They have remained invisible so far to all other telescopes. INTEGRAL was launched exactly one year ago today to study the most energetic phenomena in the universe.

For more information, see the ESA Science News Release (SNR-21-2003):
ESA's INTEGRAL discovers hidden black holes

Happy Anniversary INTEGRAL!

01 October 2003 This month (October 17) we celebrate the first year of INTEGRAL in orbit. We have therefore selected a special one-year anniversary picture this month. It shows an image obtained with the Qualification Model of the ISGRI detector using 122 keV radiation - back in 1999......

The INTEGRAL ISOC Newsletter #9 is on-line

12 September 2003 ISOC Newsletter #9

See also the previous issues of the ISOC Newsletter.

The AO-2 deadline has closed.

05 September 2003 The response from the scientific community was again very impressive. All proposals are subject to an independent peer review by the Time Allocation Committee during the month of October. The AO-2 programme will be announced in October. Further details will be made available in the forthcoming issue of the ISOC newsletter.

Release of the second Announcement of Opportunity (AO-2) for observing proposals with INTEGRAL

15 July 2003 Today, the Director of Science has released the second Announcement of Opportunity (AO-2) for observing proposals with INTEGRAL. More information can be found under the AO-2 documentation page and the INTEGRAL homepage (AO-2 section).

The INTEGRAL ISOC Newsletter #8 is on-line

26 June 2003 ISOC Newsletter #8

See also the previous issues of the ISOC Newsletter.

The new INTEGRAL source IGR J16358-4726

10 April 2003 During part of the Galactic Centre Deep Exposure on 19-03-2003 a new bright (50 mCrab) source was detected by INTEGRAL. The source flux varied by a factor of about 2 on time scales of hours. It has been designated IGR J16358-4726 and reported in the IAU Circular No. 8097 by Revnivtsev et al.

It can been seen right in the centre of the following INTEGRAL/IBIS image, surrounded by other bright X-ray sources towards the galactic centre. The image was obtained in the 15-40 keV energy range and the plot axes show the galactic longitude and latitude.

Analysis of the archival data of ASCA and BeppoSAX observations reveals a weak X-ray source at position consistent with that of X-ray transient IGR J16358-4726 (see Revnivtsev et al. ATEL #131).

On 24-03-2003 IGR J16358-4726 was observed serendipitously with the Chandra X-ray Observatory, as reported by Kouveliotou et al. (IAU Circular No. 8109). Pulsations with a period of 5850s were detected in the x-ray light curve with an energy-dependent amplitude. The origin of these pulsations is still unclear.

A gamma-ray burst bonanza

24 March 2003 ESA's INTEGRAL satellite is detecting gamma-ray bursts at a rate of nearly one per day, establishing itself as a key player in the hunt for these enigmatic explosions.

Launched in October 2002, INTEGRAL has just captured four bursts in the last four months right in the middle of its field of view. Such precision observations are providing scientists with a remarkable view of gamma-ray bursts, which occur randomly, fade within seconds, and yet shine with the intensity of millions upon millions of Suns.

For more information, see the ESA Science web note: A gamma-ray burst bonanza

INTEGRAL discovers new transient (IGR J16318-4848)

14 February 2003 During the galactic plane scan on 29-01-2003 a new bright (50-100 mCrab) source was detected close (~1o) to the well-known Black Hole Candidate 4U 1630-47. This first INTEGRAL transient source was desginated IGR J16318-4848 and reported in IAU circular 8063 by Courvoisier et al. It is visible in the INTEGRAL picture of the month February (POMFeb2003.html) as the bright spot to the right and below 4U 1630-47.

Luckily this new transient was also in the field of view during the observations of 4U 1630-47 (INTEGRAL's first TOO; PI Tomsick) which were performed from 01-02-2003 to 05-02-2003. The transient source was variable during this observation, and was sometimes fainter than 10 mCrab.

Follow-up observations were performed with RXTE on 03-02-2003 and XMM-Newton on 10-02-2003. RXTE detected a 3 mCrab source (which was much fainter than during the INTEGRAL discovery observation) at a position which was possibly not consistent with the INTEGRAL position. However, the observation with XMM-Newton revealed a highly absorbed, variable source (0.2-0.75 cts/s in the PN) consistent with the INTEGRAL position. Schartel et al. reported on the XMM observation in IAUC 8072. Preliminary XMM results can be found on http://xmm.esac.esa.int/external/xmm_news/items/IGR/ (including a beautiful spectrum containing two iron lines).

Murakami et al. reported in AUC 8070 that the source was also found in ASCA archival observation back in September 1994 at a level of about 2 mCrab and a hint of an iron emission line.

The INTEGRAL ISOC Newsletter #7 is on-line

23 January 2003 ISOC Newsletter #7

See also the previous issues of the ISOC Newsletter.