New high energy γ-ray sources observed by COS B

LOCALISED γ-ray sources contribute to the overall galactic emission; some of these sources have been identified with known astronomical objects1,2, while several unidentified γ-ray sources have also been reported3,4. We describe here a search for γ-ray sources using data from the ESA γ-ray satellite COS B which revealed 10 new unidentified sources. These sources seem to be galactic with typical γ-ray luminosities above 100 MeV in excess of 1035 erg s−1.

Panel Discussion: Systems for Data Analysis What they AEE; what they Could be?

CRANE: I’d like to pose a couple of questions: (1) Command Languages — A tool for the astronomer or for the programmer? (2) Portability — Holy Cow or Red Herring? I propose that we start with the first one and see how far we get. If we don’t get past that, fine. If we get on to the question of portability, this is also fine. Let me just open up the discussion by asking Rudi Albrecht to make a comment.

Panel Discussion on “ how can Computer Science Contribute to the Solution of Problems Posed by Astronomers ?”

A Panel was hold on June 3rd summarizing, in a way, the guide- lines and the aims of the Workshop. General questionswere addressed to M.Disney, E.Groth and D.Wells, who have expressed in the Workshop the point of view from Astronomy in the Sections “Data Analysis methodologies”, “Image processing” and “Systems for Data Analysis” respectively:

Panel Discussion on Data Analysis Trends in X-Ray and γ-Ray Astronomy 30/5/84, 11°°–12°°

[The text of the panel has been edited by Dr. ozel (with indispensable help from Gabi Breuer, secretary of MPIfR) from a tape recording. The words not completely understandable are noted by (?), while various inclusions for the continuity of the text are indicated by [ ]. The slides and viewgraphs presented in the panel are added as Figures and Tables.]

Observability of γ-ray pulsars

PULSARS seem to play a major role as γ-ray emitters. Of the 13 objects listed in the first COS B catalogue1 the two brightest, CG185-5 and CG263-2, have been identified with the Crab (PSR0531+21) and Vela (PSR0833–;45) pulsars respectively. This privileged role of pulsars as identified γ-ray sources could be simply related to observational reasons: in fact, because of the poor angular resolution intrinsic to the γ-ray telescopes, the only possibility of identification for individual sources is the time structure of the emission, and the periodical pattern of pulsars is particularly suited. On the other hand, for PSR0531+21 and PSR0833−45, the observed pulsed energy release is essentially in…

Search for Pulsed Gamma Ray Emission above 50 MeV from NP 0532

OBSERVATIONS of the pulsar NP 0532 in the gamma ray region have yielded evidence of pulsed gamma ray emission for energies up to 10 MeV (refs. 1, 2 and Kurfess, to be published). Above this energy, upper limits between 10 MeV and 150 MeV (refs. 3, 4) and above 50 MeV (ref. 5) are indicated. A result above 70 MeV with phase error of 3 ms with respect to optical signal has been given by a counter experiment6.

The Extreme Energy Cosmic Rays and Cosmic Neutrinos as Probes for the Distant Universe. Astrophysics Involved and Experimental Approach

The Cosmic Radiation, with its charged and neutral components, can be considered the second fundamental channel for the investigation of the Universe complementing the “Electromagnetic” specific of the conventional Astronomy. The experimental approach considered here is based on the observation from a Low Orbit Satellite of the UV fluorescence signal produced in the Earth atmosphere by the incoming radiation. A general description is given of the AIR WATCH/OWL experiment; some detail will also be given of “EUSO”: Extreme Universe Space Observatory” a proposal which is being submitted to the European Space Agency in response to an Announcement of Opportunity (AO) issued on October 1999.

Feasibility of 1 arcmin resolution gamma-ray air-Čerenkov multiple telescope experiment

Abstract In this paper we discuss the feasibility of a ground based detector exploiting the technique of Cerenkov light stereo imaging of air showers for the detection of discrete cosmic sources of γ-rays with energy threshold of 100 GeV, angular resolution (HWHM) of 1 arcmin ( 1 3 mrad), cosmic ray background rejection ≥ 99%. This experiment will make possible a deep survey of the sky with sensitivity of 1 100 of the Crab in 45 h of exposure.

Bepposax: 3 Years of Operation

BeppoSAX, the X-Ray Astronomy satellite operating in the (0.1–300) keY energy band has now lived more than 30.000 hours in orbit and it is halfway to complete the 3rd round of observations (A03 started at the beginning of may 1999 and it will end in April 2000). A report is given on the general fields covered by the mission and on the more relevant results obtained. The satellite is in excellent operating conditions and it is foreseen to continue the observational life-time well beyond the initially scheduled 3 years.

COS B observation of high-energy γ radiation from 3C273

THE discovery of a high-energy γ-ray source at α(1950) = 12h 29 min±6 min, δ(1950)= +3°±1.5° is reported here. Arguments are given for the identification with 3C273. If this identification is correct, the γ-ray luminosity of 3C273 in the energy range 50–500 MeV is 2×1046 erg s−1 for H0 = 60 km s−1 Mpc−1.

The Sax Mission for X-Ray Astronomy

The satellite for X-ray astronomy SAX, to be launched at the end of 1993, is devoted to systematic, integrated and comprehensive, studies of galactic and extra-galactic sources in the energy band 0.1–200 keV, and is under joint development by the Italian Space Agency (ASI) and the Netherlands Agency for Aerospace programs (NIVR), with the participation of SRU/SRON and SSD/ESTEC. The basic scientific objectives can be summarized as follows: — Broad band spectroscopy (E/△ E=12) from 0.1–10 keV with imaging resolution of 1 arcmin. — Continuum and line spectroscopy (E/△ E=5-20) in the energy range 3–200 keV. — Variability studies of bright source energy spectra on timescales from milliseconds t…

The X-ray Facility at LAX in Palermo

A description is given of the X-ray facility installed at LAX (Laboratorio per Sperimentazioni con Radiazioni X), jointly operated in Palermo by the DEAF (Department of Energy and Physics Applications) of the University of Palermo and the IFCAT (Institute of Cosmic Physics and Informatics) of the Italian National Research Council. The X-rays are produced by bombarding a target with energized electrons up to 60 keV. Depending on the material of the target, characteristic fluorescence lines as well as continuous bremsstrahlung is emitted. The X-ray beam has an operational energy range of 0,1–25 keV with a flux of 1010–1012 photons/sr · s; the beam, collimated on a length of 10,5 m, has a diam…

COS-B OBSERVATION OF THE MILKY WAY IN HIGH-ENERGY GAMMA RAYS

Rejection Power of A Horizontal Rpc Telescope For Left and Right Coming Cosmic Muons

Abstract The possibility of performing neutrino astronomy by means of a detector above the ground depends critically on the feasibility of a rejection power on the order of 10 11 required to discriminate the enormous background of cosmic downward going muons from the signal of upward going muons produced by neutrinos. In order to check whether and how this rejection is obtainable, we have built in the Physics Department of the University of Bari a horizontal cosmic muon telescope (MINI) instrumented with resistive plate counters. By performing time-of-flight measurements, we have estimated the rejection power of our telescope for left and right coming cosmic muons. The rejection dependence …

On the identification of celestial γ-ray sources

THE observations from COS B have provided a new and more detailed picture of the high energy γ-ray emission from the Galaxy. We discuss here the first catalogue with 13 localised sources which has been compiled1,2 and how the list should lengthen in the near future, as the data analysis progresses.

Angular resolution of an array of tracking-chamber detectors for use in high-energy gamma-ray astronomy

We describe a method of analysis for the reconstruction of the arrival direction of a high-energy photon impacting on the top of the atmosphere by using the directions of the particles on the shower front as measured by a ground-based array of tracking chambers uniformly distributed on a square surface; as an example, an array with enclosed surface of (120×120) m2 has been considered. Estimates on the accuracy of reconstruction are given, after application of the method to computer-simulated shower directions as a function of the number of «smapling» detectors and of their accuracy in the measurement of the «local» shower direction.

Possible pulsed gamma ray emission above 50 MeV from the Crab pulsar.

A SEARCH for pulsed gamma ray emission from NP 0532 has been carried out with a balloon-borne experiment using a spark chamber as the central detector. This pulsar, situated in the Crab Nebula, is already known to pulsate in the radio, optical and X-ray range1–5.

Panel Discussion on Data Analysis Trends in X-Ray and Gamma-Ray Astronomy

ZIMMERMANN: Let me begin the panel discussion on Data Analysis Trends in X-ray and Gamma-ray astronomy by first introducing the panel members. These are from the left to the right: Roland Diehl, Ethan Schreier, Rosolino Buccheri, Livio Scarsi, Jean-Marc Chassery and Wolfgang Voges. With the exception of Jean-Marc Chassery, who is an expert on image processing and statistical analysis, all the others have longer experience in the X-ray and Gamma-ray fields. May I ask the speakers to keep their contributions to not more than five minutes, in order to allow ample room for discussion with the audience.

FIGARO IV: Large-area balloon-borne telescope to study rapid time variabilities in the gamma-ray sources at energies above 50 MeV

We present a new γ-ray telescope based on the Limited Streamer Tube technology, used as tracking chambers to detect photons above 100 MeV. This technique allows to obtain very large sensitive areas (16 m2 in our experiment), together with a good angular resolution for payloads embarcable in high-altitude balloon flights. The capability to collect a large signal in a short exposure time makes the telescope particularly suitable and competitive with respect to satellite-based detectors for studying both periodic and random time variabilities on galactic and extragalactic γ-ray sources.

Panel Discussion on Trends in Optical and Radio Data Analysis

Albrecht: What I want to do is to give a brief five-minute introduction to the subject, justifying the title which puts optical and radio astronomy in one and the same category, which I believe it is, as far as data analysis is concerned, and then I will ask the panel members to give us two-minute statements of their opinions on the subject and then I would like to ask the audience to fire questions at us.