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| ISOC Newsletter #14 |
Contents
- 3rd Announcement of Opportunity
- Mission Status
- INTEGRAL science workshop
- Science Operations - Highlights
- ISOC at ESAC - latest news
- List of approved open time AO-3 observations
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| Publication date: 01 Feb 2005 |
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| ISOC Newsletter #13 |
Contents
- 3rd Announcement of Opportunity (AO-3)
- Science Highlights
- Mission Status
- INTEGRAL Public Data Archive
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| Publication date: 05 Nov 2004 |
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| Hard X-ray view of the past activity of Sgr A* in a natural Compton mirror |
| We report the association of the recently discovered hard X-ray source IGR J17475-2822 with the giant molecular cloud Sgr B2 in the Galactic Center region. The broad band (3-200 keV) spectrum of the source constructed from data of different observatories strongly supports the idea that the X-ray emission of Sgr B2 is Compton scattered and reprocessed radiation emitted in the past by the Sgr A* source. We conclude that 300-400 years ago Sgr A* was a low luminosity (L~ 1.5×1039 erg s-1 at 2-200 keV) AGN with a characteristic hard X-ray spectrum (photon index Gamma ~ 1.8). We estimate the mass and iron abundance of the Sgr B2 scattering gas at 2×106 MSun(r/10 pc)² and 1.9 solar, respectively (where r is the radius of the cloud). |
| Publication date: 15 Oct 2004 |
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| ISOC Newsletter #12 |
| ISOC is completing the preparations for the
forthcoming Announcement of Opportunity
(AO-3) which will be released on 13 September
2004 calling for new INTEGRAL observing
proposals for the period February 2005
until August 2006. |
| Publication date: 08 Sep 2004 |
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| ESA SP-1276: ESA's Report to the 35th COSPAR Meeting |
Scientific editor: A. Gimenez
Editor: A. Wilson
The report for the 35th COSPAR Meeting covers, as in previous issues, the missions
of the Scientific Programme of ESA in the areas of astronomy, Solar System
exploration and fundamental physics. This year's COSPAR Meeting occurs only
weeks after the Saturn-orbit insertion of the Cassini spacecraft - carrying Europe's
Huygens probe to explore the atmosphere of Titan - and at the same time as the
launch of the second satellite of the Double Star project. |
| Publication date: 15 Jun 2004 |
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| The First IBIS/ISGRI Soft Gamma-Ray Galactic Plane Survey Catalog |
| We report the first high-energy survey catalog obtained with the IBIS gamma-ray imager on board INTEGRAL. The analysis has been performed on the first-year Core Program ISGRI data comprising both Galactic Plane Scan and Galactic Centre Deep Exposure pointings for a total exposure time exceeding 5 Ms. This initial survey has revealed the presence of ~120 sources detected with the unprecedented sensitivity of ~1 mcrab in the energy range 20-100 keV. Each source is located to an accuracy between 1' and 3', depending on its brightness. The outstanding IBIS capability to locate soft gamma-ray emitters has allowed us to identify most of the detected sources with already known Galactic X-ray binary systems, while 28 of the objects are of unknown nature. |
| Publication date: 20 May 2004 |
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| High-energy observations of the state transition of the X-ray nova and black hole candidate XTE J1720-318 |
| We report the results of extensive high-energy observations of the X-ray transient and black hole candidate XTE J1720-318 performed with INTEGRAL, XMM-Newton, and RXTE. |
| Publication date: 14 May 2004 |
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| ISOC Newsletter #11 |
| INTEGRAL is performing very well and we have witnessed a number of key events in the recent months which will be addressed in more detail here. Consequently this issue of the ISOC Newsletter is a bit longer than usual. |
| Publication date: 31 Mar 2004 |
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| Compact sources as the origin of the soft gamma-ray emission of the Milky Way |
| The Milky Way is known to be an abundant source of gamma-ray photons, now determined to be mainly diffuse in nature and resulting from interstellar processes. In the soft gamma-ray domain, point sources are expected to dominate, but the lack of sensitive high-resolution observations did not allow for a clear estimate of the contribution from such sources. Even the best imaging experiment revealed only a few point sources, accounting for about 50% of the total Galactic flux. Theoretical studies were unable to explain the remaining intense diffuse emission. Investigating the origin of the soft gamma-rays is therefore necessary to determine the dominant particle acceleration processes and to gain insights into the physical and chemical equilibrium of the interstellar medium. Here we report observations in the soft gamma-ray domain that reveal numerous compact sources. We show that these sources account for the entirety of the Milky Way's emission in soft gamma-rays, leaving at most a minor role for diffuse processes. |
| Publication date: 18 Mar 2004 |
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| First science with INTEGRAL |
| This 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. |
| Publication date: 17 Nov 2003 |
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| ISOC Newsletter #10 |
Several important INTEGRAL events took
place during the last two months.
We celebrated the first launch anniversary, on
17 October, with the spacecraft in excellent
shape. Unfortunately, recent high solar activity
substantially interrupted the observing programme,
for the first time. |
| Publication date: 14 Nov 2003 |
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| INTEGRAL - 1 Year in Orbit |
| A special ESA publication to coincide with the 1st annivsary of the launch of the INTEGRAL spacecraft. Contribution were made by various members of the entire mission and project teams to give a unique account of a year in the life of a spacecraft. |
| Publication date: 01 Nov 2003 |
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| Star-forming complexes and the spiral structure of our Galaxy |
| We have carried out a multiwavelength study of the plane of our Galaxy in order to establish a star-forming-complex catalogue which is as complete as possible. Features observed include H alpha, H109 alpha, CO, the radio continuum and absorption lines. For each complex we have determined the position, the systemic velocity, the kinematic distance and, when possible, the stellar distance and the corresponding uncertainties. All of these parameters were determined as homogeneously as possible, in particular all the stellar distances have been (re)calculated with the same calibration and the kinematic distances with the same mean Galactic rotation curve. Through the complexes with stellar distance determination, a rotation curve has been fitted. It is in good agreement with the one of Brand & Blitz (1993). We also investigated the residual velocities relative to the circular rotation model. We find that departures exist over large areas of the arms, with different values from one arm to another. From our data and in good agreement with previous studies, the Galactic warp is observed. It does not seem correlated with the departures from circular rotation. Finally, as segment-like features are noted from the complexes' distribution, we tried to find if they are indicative of a larger underlying structure. Then, we attempted to interpret the complexes' distribution in terms of spiral structure by fitting models with two, three and four logarithmic spiral arms. The four-arm model seems more appropriate to represent the grand design of our Galaxy. In this model the Norma arm and the external arm appear as being the two extremities of a single arm called the Norma-Cygnus arm. The new data and fitted model confirm the four-segment model of Georgelin & Georgelin (1976), clarifying the arms' design and extension and doubling their known length. |
| Publication date: 01 Jan 2003 |
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| ESA SP-1259: ESA's Report to the 34th COSPAR Meeting |
Scientific editor: B. Foing
Editor: A. Wilson
The report to the 34th COSPAR Meeting covers the missions of the Scientific Programme of ESA in the areas of astronomy, Solar System exploration and fundamental physics. |
| Publication date: 01 Oct 2002 |
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| INTEGRAL Ready to Fly |
| The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) is a truly international enterprise. While ESA is responsible for the overall mission, the satellite's development and the flight operations, the launcher is provided by the Russian Space Agency and the second ground station is provided by NASA. The scientific instruments and the Science Data Centre are provided by the mission's Principal Investigators, with funding from national organisations. |
| Publication date: 01 Aug 2002 |
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| The Integral core Observing Programme |
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| Publication date: 01 Jun 2001 |
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| The COMPTEL 1.809 MeV Survey |
| We present the latest update of the 1.809 MeV sky survey obtained with COMPTEL. Based on all observations taken since the launch of CGRO in spring 1991 to early summer this year we obtain 1.809 MeV all sky maps using different imaging methods. The background is modelled on the basis of an adjacent energy approach. We confirm the previously reported characteristics of the galactic 1.809 MeV emission, specifically excesses in regions away from the inner Galaxy. The observed 1.8 MeV gamma-ray line is ascribed to the radioactive decay of 26Al in the interstellar medium. 26Al has been found to be predominantly synthesised in massive stars and their subsequent core-collapse supernovae, which is confirmed in tracer comparisons. Due to this, one anticipates flux enhancements aligned with regions of recent star formation, such as apparently observed in the Cygnus and Vela regions. |
| Publication date: 03 Apr 2001 |
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| The Integral Spacecraft - In the Proceedings of the 3rd INTEGRAL Workshop |
The INTErnational Gamma Ray Astrophysics Laboratory (INTEGRAL) is being developed by ESA
as the second medium-size satellite of the long-term scientific plan Horizon 2000. It is an
observatory providing an excellent opportunity to the scientific community for detailed imaging and
high-resolution spectroscopy of Gamma-ray sources.
After completion of the design and development phase the Structural Thermal Model of the Integral
Spacecraft and its four scientific instruments is presently being tested. First tests took place in
spring 1998 at the ESTEC test facilities. Late summer 1998 the Engineering Model test campaign
will follow.
This paper summarises the key programmatic milestones of the project, highlights the final design
characteristics of the satellite, reports on the first test results, and describes the orbital scenario of the mission and the herewith-related requirements to the satellite. |
| Publication date: 13 Oct 2000 |
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| Proceedings of the 5th Compton Symposium |
| The spectrometer on INTEGRAL (SPI) is one of the two main telescopes of the future INTEGRAL observatory. SPI is made of a compact hexagonal matrix of 19 high-purity germanium detectors shielded by a massive anticoincidence system. A HURA type coded aperture modulates the astrophysical signal. The spectrometer system, its physical characteristics and performances are presented. The instrument properties such as imaging capability, energy resolution and sensitivity have been evaluated by means of extensive Monte-Carlo simulations. With the expected performances of SPI, it will be possible to explore the gamma-ray sky in greater depth and detail than it was possible with previous gamma-ray telescopes like SIGMA, OSSE and COMPTEL. In particular, the high-energy resolution will allow for the first time the measurement of gamma-ray line profiles. Such lines are emitted by the debris of nucleosynthesis and annihilation processes in our Galaxy. Lines from these processes have already been measured, but due to the relatively poor energy resolution, details of the emission processes in the source regions could not be studied. With the high-resolution spectroscopy of SPI such detailed investigations will be possible. |
| Publication date: 16 Sep 1999 |
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| Proceedings of the 5th Compton Symposium |
| The International Gamma-Ray Astrophysics Laboratory (INTEGRAL), to be launched in 2001, is dedicated to the fine spectroscopy (DE: 2 keV FWHM @ 1.3 MeV) and fine imaging (angular resolution: 12' FWHM) of celestial gamma-ray sources in the energy range 15 keV to 10 MeV with concurrent source monitoring in the X-ray (3-35 keV) and optical (V, 550 nm) range. The mission is conceived as an observatory led by ESA with contributions from Russia and NASA. The INTEGRAL observatory will provide to the science community at large an unprecedented combination of imaging and spectroscopy over a wide range of gamma-ray energies. This paper summarises the key scientific goals of the mission, the current development status of the payload and spacecraft and it will give an overview of the science ground segment including the science data center, science operations and key elements of the observing program. |
| Publication date: 16 Sep 1999 |
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