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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

4255 results found.

  1. LIGO/Virgo S200302c: AstroSat CZTI upper limits
  2. GRB200210A AstroSat observations
  3. LIGO/Virgo S200302c: No counterpart candidates in KAIT observations
  4. LIGO/Virgo S200225q: AstroSat CZTI upper limits
  5. LIGO/Virgo S200219ac: AstroSat CZTI upper limits
  6. LIGO/Virgo S200302c: Upper limits from IceCube neutrino searches
  7. GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
  8. LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
  9. GRB 200228B: LCO Optical Upper Limit
  10. GRB 200228B: Liverpool Telescope imaging
  11. GRB 200227A: Swift-BAT refined analysis
  12. GRB 200224A: Mondy optical upper limit
  13. LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
  14. GRB 200227A: Swift detection of a burst
  15. Konus-Wind observation of GRB 200219A
  16. LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
  17. Fermi trigger No 604231129: Global MASTER-Net observations report
  18. LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
  19. LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
  20. LIGO/Virgo S200224ca: Global MASTER-Net observations report
  21. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  22. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  23. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  24. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  25. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  26. LIGO/Virgo S200219ac: Upper limits from IceCube neutrino searches
  27. GRB 200219A: Swift detection of a short burst
  28. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  29. LIGO/Virgo S200213t: AstroSat CZTI upper limits
  30. LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
  31. LIGO/Virgo S200213t: Pre-discovery detections of MASTER OT J044008.76-651302.3
  32. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  33. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  34. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  35. LIGO/Virgo S200213t: Candidates from the Zwicky Transient Facility
  36. LIGO/Virgo S200213t: 1 counterpart neutrino candidate from IceCube neutrino searches
  37. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  38. LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
  39. LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
  40. Fermi trigger No 602817262: Global MASTER-Net observations report
  41. GRB 200205B: Swift-BAT refined analysis
  42. GRB 200205B: Swift/UVOT Detection
  43. GRB 200205B: Enhanced Swift-XRT position
  44. GRB 200205B: Swift detection of a burst with optical counterpart
  45. Fermi trigger No 602455182: Global MASTER-Net observations report
  46. Re-classification of Fermi GBM triggers 200203137, 200203156/GRB200203A and 200203861
  47. LIGO/Virgo S200129m: Upper limits from Konus-Wind observations
  48. Fermi trigger No 602392636: Global MASTER-Net observations report
  49. GRB 200131A: Swift detection of a burst with an optical counterpart
  50. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  51. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  52. LIGO/Virgo S200129m: Upper limits from CALET observations.
  53. LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
  54. LIGO/Virgo S200129m: Global MASTER-Net observations report
  55. GRB 200129A: Fermi GBM Final Real-time Localization
  56. LIGO/Virgo S200129m: upper limits from AGILE/GRID observations
  57. LIGO/Virgo S200129m: upper limits from AGILE/MCAL observations
  58. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
  59. LIGO/Virgo S200129m: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  60. LIGO/Virgo S200129m: Upper limits from IceCube neutrino searches
  61. LIGO/Virgo S200129m: Identification of a GW compact binary merger candidate
  62. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  63. Fermi-LAT-ANTARES coincidence
  64. GRB 200125B: DDOTI/OAN optical observations report
  65. LIGO/Virgo S200128d: Upper limits from IceCube neutrino searches
  66. Fermi trigger No 601841483: Global MASTER-Net observations report
  67. Fermi trigger No 601729856: Global MASTER-Net observations report
  68. Fermi trigger No 601677816: Global MASTER-Net observations report
  69. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  70. GRB 200122A: Optical upper limit
  71. LIGO/Virgo S191222n: AstroSat CZTI upper limits
  72. LIGO/Virgo S200112r: AstroSat CZTI upper limits
  73. LIGO/Virgo S200114f: AstroSat CZTI upper limits
  74. LIGO/Virgo S200115j: Zwicky Transient Facility search for optical counterparts to Swift X-ray sources
  75. Fermi trigger No 601363105: Global MASTER-Net observations report
  76. Fermi trigger No 601254300: Global MASTER-Net observations report
  77. LIGO/Virgo S191216ap: Upper limits from Konus-Wind observations
  78. IceCube Alert 200120.78: Global MASTER-Net observations report
  79. IceCube 200117A: No significant detection in HAWC
  80. LIGO/Virgo S191129u: Upper limits from Konus-Wind observations
  81. LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
  82. IceCube-200117A: No Neutrino Counterpart in ANTARES data
  83. LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
  84. GRB 200115A: CALET Gamma-Ray Burst Monitor detection
  85. IceCube-200117A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
  86. LIGO/Virgo S200115j: Swift-XRT sources
  87. LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
  88. LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
  89. LIGO/Virgo S200114f: No counterpart in targeted WHT/ACAM imaging
  90. LIGO/Virgo S200115j: Upper limits from IceCube neutrino searches
  91. LIGO/Virgo S200114f: No Counterparts in DDOTI/OAN Optical Observations
  92. IceCube-200109A: Candidate Counterparts from the Zwicky Transient Facility
  93. LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
  94. Fermi trigger No 600666048: Global MASTER-Net observations report
  95. LIGO/Virgo S200114f: Upper limits from IceCube neutrino searches
  96. LIGO/Virgo S200112r: Upper limits from IceCube neutrino searches
  97. IceCube 200109A: No significant detection in HAWC
  98. Fermi trigger No 600448273: Global MASTER-Net observations report
  99. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  100. Swift GRB 200107B: Global MASTER-Net observations report

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