scholarly journals The ALEXIS Point Source Detection Effort

1996 ◽  
Vol 152 ◽  
pp. 485-489
Author(s):  
Diane Roussel-Dupré ◽  
Jeff Bloch ◽  
Sean Ryan ◽  
Bradley Edwards ◽  
Timothy Pfafman ◽  
...  
Keyword(s):  
Point Source ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Point Sources ◽  
Cataclysmic Variable ◽  
Spacecraft Attitude ◽  
Source Detection ◽  
Euv Emission ◽  
New Methods ◽  
Better Than

Los Alamos National Laboratory’s ALEXIS satellite (a wide area EUV monitoring instrument) was launched April 25, 1993. Due to the damage sustained at launch by the satellite, the ALEXIS project team has had to spend over a year devising new methods to determine spacecraft attitude knowledge, essential for putting photons back on the sky correctly. These efforts have been successful and currently the ALEXIS attitude solutions are precise to better than 0.5 degree close to the original 0.25 degree pre-flight specification. This paper will discuss the number and types of point sources that have been revealed in the ALEXIS data to date. We will also discuss ALEXIS observations of the June, 1994 super outburst of the Cataclysmic Variable VW Hyi, a program to look for simultaneous EUV emission from Gamma Ray Bursts, as well as an effort to detect EUV transients with a 12 – 24 hour response time.

A REVIEW OF PARTICLE ASTROPHYSICS WITH ICECUBE

2012 ◽  
Vol 27 (39) ◽  
pp. 1230042 ◽  
Author(s):  
IGNACIO TABOADA
Keyword(s):  
Dark Matter ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Point Sources ◽  
Cherenkov Light ◽  
Atmospheric Neutrinos ◽  
Neutrino Detector ◽  
Secondary Particles ◽  
Particle Astrophysics

IceCube is a neutrino detector sensitive to energies above 10 GeV. IceCube operates by sensing the Cherenkov light from secondary particles produced in neutrino-matter interactions. One gigaton of highly transparent Antarctic ice is instrumented to achieve this goal. Designed to be modular, IceCube has been collecting data since construction began in 2005. Construction was completed in December 2010. The primary goal of IceCube is to observe astrophysical sources of neutrinos. We present here a summary of IceCube's recent results in atmospheric neutrinos, point sources, diffuse fluxes of neutrinos, cosmogenic neutrinos, a lack of correlation between neutrinos and Gamma Ray Bursts and the search for dark matter.

scholarly journals On the detection of point sources in Planck LFI 70 GHz CMB maps based on cleaned K-map

2015 ◽  
Vol 30 (14) ◽  
pp. 1550083
Author(s):  
H. G. Khachatryan ◽  
A. L. Kashin ◽  
E. Poghosyan ◽  
G. Yegoryan
Keyword(s):  
Cosmic Microwave Background ◽  
Point Source ◽  
Temperature Data ◽  
Point Sources ◽  
Detection Technique ◽  
Source Detection ◽  
Microwave Background ◽  
Probe Point ◽  
Cmb Temperature ◽  
Planck Satellite

We use the Planck LFI 70 GHz data to further probe point source detection technique in the sky maps of the cosmic microwave background (CMB) radiation. The method developed by Tegmark et al. for foreground reduced maps and the Kolmogorov parameter as the descriptor are adopted for the analysis of Planck satellite CMB temperature data. Most of the detected points coincide with point sources already revealed by other methods. However, we have also found nine source candidates for which still no counterparts are known.

scholarly journals The Transient EUV Sky as Observed by Alexis

1996 ◽  
Vol 158 ◽  
pp. 257-258
Author(s):  
Diane Roussel-Dupré ◽  
Jeffery J. Bloch
Keyword(s):  
Point Source ◽  
Cataclysmic Variables ◽  
Field Of View ◽  
Spacecraft Attitude ◽  
Wide Field ◽  
Survey Experiment ◽  
Energy Bands ◽  
New Methods ◽  
Wide Field Of View ◽  
Sky Monitor

Los Alamos National Laboratory’s ALEXIS satellite, containing six wide field of view EUV telescopes was launched 1993 April 25. ALEXIS is a sky monitor/survey experiment, and with each 50 s rotation, the satellite’s six telescopes (three energy bands 130, 178 and 186 Å) scan nearly half of the sky. Due to the damage sustained at launch by the satellite, the ALEXIS project team has had to spend over a year devising new methods to determine spacecraft attitude knowledge, essential for putting photons back on the sky correctly. These efforts have been successful. A recent review of the ALEXIS point source effort can be found in the Proceedings of IAU Colloquium 152, 1995. This paper reviews the transient systems that have been observed by ALEXIS which fall into two types: cataclysmic variables and unknown, short duration transients.

FIELD RELEASES OF TRICHOGRAMMA MINUTUM (HYMENOPTERA: TRICHOGRAMMATIDAE) FOR SUPPRESSION OF EPIDEMIC SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE), EGG POPULATIONS IN MAINE

1984 ◽  
Vol 116 (10) ◽  
pp. 1357-1366 ◽  
Author(s):  
Mark W. Houseweart ◽  
Daniel T. Jennings ◽  
Robert K. Lawrence
Keyword(s):  
Point Source ◽  
Choristoneura Fumiferana ◽  
Single Point ◽  
Spruce Budworm ◽  
Point Sources ◽  
Slight Improvement ◽  
Parasitism Rates ◽  
Trichogramma Minutum ◽  
Multiple Releases ◽  
Better Than

AbstractTrichogramma minutum Riley was released in the field for suppression of epidemic spruce budworm, Choristoneura fumiferana (Clemens), egg populations in Maine from 1977 to 1981. Commercially reared California-strain T. minutum were released from the ground at single-point sources in 1977. In 1978, using 4-point-source releases, we found that the native Maine-strain performed better than the California strain. In 1979, broadcast and multiple releases from the ground gave slight improvement in parasitism over 4-point releases. In 1981, three closely timed, aerially broadcast releases from a helicopter yielded increases in parasitism rates significantly higher than those in control plots, but not sufficient to suppress epidemic spruce budworm populations. Important variables and suggestions for future aerial releases are discussed.

Neutrino astronomy and gamma-ray bursts

2007 ◽  
Vol 365 (1854) ◽  
pp. 1323-1334 ◽  
Author(s):  
Eli Waxman
Keyword(s):  
Cosmic Rays ◽  
Gamma Ray ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
Current State ◽  
Open Questions ◽  
Neutrino Astronomy ◽  
Better Than

The construction of large-volume detectors of high energy, greater than 1 TeV, neutrinos is mainly driven by the search for extragalactic neutrino sources. The existence of such sources is implied by the observations of ultra-high-energy, greater than or equal to 10 19  eV, cosmic rays, the origin of which is a mystery. In this lecture, I briefly discuss the expected extragalactic neutrino signal and the current state of the experimental efforts. Neutrino emission from gamma-ray bursts (GRBs), which are probably sources of both high-energy protons and neutrinos, is discussed in some detail. The detection of the predicted GRB neutrino signal, which may become possible in the coming few years, will allow one to identify the sources of ultra-high-energy cosmic rays and to resolve open questions related to the underlying physics of GRB models. Moreover, detection of GRB neutrinos will allow one to test for neutrino properties (e.g. flavour oscillations and coupling to gravity) with an accuracy many orders of magnitude better than is currently possible.

Point-Source Detection Using Gamma-Ray Spectra in Radiation-Portal Monitoring

2013 ◽  
Vol 45 (3) ◽  
pp. 285-296
Author(s):  
Tom Burr ◽  
Michael S. Hamada ◽  
Kary Myers ◽  
Misha Skurikhin
Keyword(s):  
Point Source ◽  
Gamma Ray ◽  
Source Detection

scholarly journals Two populations are better than one: Short gamma-ray bursts from SGR giant flares and NS-NS mergers

2008 ◽  
Author(s):  
Robert Chapman ◽  
Robert S. Priddey ◽  
Nial R. Tanvir ◽  
C. Bassa ◽  
Z. Wang ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Two Populations ◽  
Better Than

scholarly journals The C-Band All-Sky Survey: total intensity point-source detection over the northern sky

2020 ◽  
Vol 496 (2) ◽  
pp. 1941-1958
Author(s):  
R D P Grumitt ◽  
Angela C Taylor ◽  
Luke Jew ◽  
Michael E Jones ◽  
C Dickinson ◽  
...  
Keyword(s):  
Point Source ◽  
Flux Density ◽  
Detection Algorithm ◽  
Point Sources ◽  
Source Detection ◽  
Diffuse Emission ◽  
Microwave Background ◽  
Mexican Hat Wavelet ◽  
Sky Survey ◽  
Source Populations

ABSTRACT We present a point-source detection algorithm that employs the second-order Spherical Mexican Hat wavelet filter (SMHW2), and use it on C-Band All-Sky Survey (C-BASS) northern intensity data to produce a catalogue of point sources. This catalogue allows us to cross-check the C-BASS flux-density scale against existing source surveys, and provides the basis for a source mask that will be used in subsequent C-BASS and cosmic microwave background (CMB) analyses. The SMHW2 allows us to filter the entire sky at once, avoiding complications from edge effects arising when filtering small sky patches. The algorithm is validated against a set of Monte Carlo simulations, consisting of diffuse emission, instrumental noise, and various point-source populations. The simulated source populations are successfully recovered. The SMHW2 detection algorithm is used to produce a $4.76\, \mathrm{GHz}$ northern sky source catalogue in total intensity, containing 1784 sources and covering declinations δ ≥ −10°. The C-BASS catalogue is matched with the Green Bank 6 cm (GB6) and Parkes-MIT-NRAO (PMN) catalogues over their areas of common sky coverage. From this we estimate the 90 per cent completeness level to be approximately $610\, \mathrm{mJy}$, with a corresponding reliability of 98 per cent, when masking the brightest 30 per cent of the diffuse emission in the C-BASS northern sky map. We find the C-BASS and GB6 flux-density scales to be consistent with one another to within approximately 4 per cent.

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