Following a description of the science drive which originated the Swift Mission, this is US NASA MIDEX Mission with the collaboration of Italy and the UK, we will describe the status of the hardware and the observing strategy. The telemetry is carried out via the TDRSS satellite for those communications that need immediate response. The data transfer and the scheduled uploading of routine commands will be done through the ASI Malindi station in Kenia. Both in the US and in Europe a large effort will be done to follow the bursts with the maximum of efficiency and as soon as possible after the alert. We will describe how the ESO VLT telescopes are able to respond to the alert. To address the problematic of the dark bursts and to immediately follow up all of the bursts also in the Near Infrared we designed and built a 60 cm NIR Robotic telescope, REM, to be located on the ESO ground at Cerro La Silla. The instrumentation includes also a low dispersion spectrograph with the capability of multi wavelength optical photometry.
view Abstract Citations (36) References (21) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS GRIS Detections of the 511 keV Line from the Galactic Center Region in 1992 Leventhal, M. ; Barthelmy, S. D. ; Gehrels, N. ; Teegarden, B. J. ; Tueller, J. ; Bartlett, L. M. Abstract The Gamma Ray Imaging Spectrometer (GRIS) was flown on balloons over Alice Springs, Australia on 1992 April 26 and May 7. A full Galactic center transit (about 12 hr) was achieved on both flights with the instrument working normally. The electron/positron annihilation line was detected on both flights. The line fluxes and line widths were found to be (7.7 +/- 1.2) x 10 exp -4 and (8.9 +/- 1.1) x 10 exp -4 photons/sq cm per sec and 1.3 +/- 0.7 and 3.6 +/- 1.0 keV, respectively. These results are compared to each other and earlier (1988) GRIS results to produce suggestive evidence for source variability. Near-contemporaneous OSSE/CGRO Galactic center observations indicate that the GRIS results cannot be due solely to a single point source like IE 1740.7-2942 within a few degrees of the Galactic center. The GRIS 1992 results represent the first time that successive high-resolution balloon measurements have been achieved on a time scale of days. Publication: The Astrophysical Journal Pub Date: March 1993 DOI: 10.1086/186757 Bibcode: 1993ApJ...405L..25L Keywords: Galactic Nuclei; Galactic Radiation; Gamma Ray Spectrometers; Imaging Spectrometers; Line Spectra; Milky Way Galaxy; Positron Annihilation; Emission Spectra; Point Sources; Spectral Line Width; Statistical Analysis; Astrophysics; GALAXY: CENTER; GAMMA RAYS: OBSERVATIONS; LINE: PROFILES full text sources ADS | data products SIMBAD (2)
The primary objective of the study of unidentified EGRET sources with INTEGRAL is to locate with a few arcminute accuracy the hard X-ray / soft gamma-ray counterparts within the EGRET error circle or to determine upper limits on their emission in the INTEGRAL energy range. The INTEGRAL Galactic Plane Scan (GPS) and Galactic Centre Deep Exposure (GCDE) data have been analysed and cross-correlated with the EGRET 3^rd Catalogue to search for counterparts of EGRET sources. The IBIS detection of a source within the EGRET error circle of 3EG J1736-2908 is presented and its possible identification with the active galaxy GRS 1734-292 is discussed. Finally, preliminary results on the cross-correlation between EGRET unidentified sources and the first data from the IBIS survey of the Galactic Centre are presented.
The Advanced LIGO observatories detected gravitational waves from two binary black hole mergers during their first observation run (O1). We present a high-energy neutrino follow-up search for the second gravitational wave event, GW151226, as well as for gravitational wave candidate LVT151012. We find two and four neutrino candidates detected by IceCube, and one and zero detected by Antares, within $\ifmmode\pm\else\textpm\fi{}500\text{ }\text{ }\mathrm{s}$ around the respective gravitational wave signals, consistent with the expected background rate. None of these neutrino candidates are found to be directionally coincident with GW151226 or LVT151012. We use nondetection to constrain isotropic-equivalent high-energy neutrino emission from GW151226, adopting the GW event's 3D localization, to less than $2\ifmmode\times\else\texttimes\fi{}1{0}^{51}--2\ifmmode\times\else\texttimes\fi{}1{0}^{54}\text{ }\text{ }\mathrm{erg}$.
We present the results of a 5 GHz survey with the Very Large Array (VLA) and the expanded VLA, designed to search for short-lived ( < ∼ 1 day) transients and to characterize the variability of radio sources at milli-Jansky levels.A total sky area of 2.66 deg 2 , spread over 141 fields at low Galactic latitudes (b ∼ = 6-8 deg) was observed 16 times with a cadence that was chosen to sample timescales of days, months and years.Most of the data were reduced, analyzed and searched for transients in near real time.Interesting candidates were followed up using visible light telescopes (typical delays of 1-2 hr) and the X-Ray Telescope on board the Swift satellite.The final processing of the data revealed a single possible transient with a flux density of f ν ∼ = 2.4 mJy.This implies a transients sky surface density of κ(f ν > 1.8 mJy) = 0.039 +0.13,+0.18-0.032,-0.038deg -2 (1, 2-σ confidence errors).This areal density is consistent with the sky surface density of transients from the Bower et al. survey extrapolated to 1.8 mJy.Our observed transient areal density is consistent with a Neutron Stars (NSs) origin for these events.Furthermore, we use the data to measure the sources variability on days to years time scales, and we present the variability structure function of 5 GHz sources.The mean structure function shows a fast increase on ≈ 1 day time scale, followed by a slower increase on time scales of up to 10 days.On time scales between 10-60 days the structure function is roughly constant.We find that > ∼ 30% of the unresolved sources brighter than 1.8 mJy are variable at the > 4-σ confidence level, presumably due mainly to refractive scintillation.
The Compton Gamma Ray Observatory was de-orbited on 4 June 2000 after 9 highly successful years in orbit. Major discoveries were made every year with Compton. We present a retrospective overview of the mission from launch to deorbit, highlighting some seminal scientific findings.
Prior to the current Compton Gamma Ray Observatory ( Compton ) mission, no comprehensive all-sky gamma-ray surveys had been performed. There were, however, some surveys performed over limited energy bands and/or over portions of the sky. These include the HEAO-A4 hard X-ray survey and the COS-B and SAS-2 high-energy gamma-ray surveys. The early work forms a basis for understanding and appreciating the Compton results, and so is reviewed in Section 2.
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