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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"

3144 results found.

  1. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  2. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  3. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  4. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  5. LIGO/Virgo S200213t: AT2020clw/ZTF20aanaoyz, AT2020crd/ZTF20aanakge and AT2020cly/ZTF20aanakes 10.4m GTC spectroscopy
  6. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  7. GRB 200219B: Fermi GBM Final Real-time Localization
  8. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  9. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  10. LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
  11. LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
  12. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  13. LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy
  14. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  15. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  16. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  17. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  18. LIGO/Virgo S200208q: Global MASTER-Net observations report
  19. Fermi trigger No 602817262: Global MASTER-Net observations report
  20. MAXI GRB200205.29: Global MASTER-Net observations report
  21. GRB 200131A: Swift detection of a burst with an optical counterpart
  22. Swift GRB200131.95: Global MASTER-Net observations report
  23. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  24. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  25. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  26. LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  27. GRB 200125A: Swift-BAT refined analysis
  28. GRB 200127A: Swift detection of a burst
  29. Fermi trigger No 601729856: Global MASTER-Net observations report
  30. Fermi trigger No 601677816: Global MASTER-Net observations report
  31. GRB 200125B: Fermi GBM Final Real-time Localization
  32. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  33. Fermi trigger No 601363105: Global MASTER-Net observations report
  34. GRB 200122A: Swift detection of a burst
  35. GRB 200120A: Fermi GBM Final Real-time Localization
  36. LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
  37. LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
  38. GRB 200115A: AROMA-N Optical Observation
  39. LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
  40. LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
  41. Baksan Neutrino Observatory Alert 200116.21: Global MASTER-Net observations report
  42. IPN triangulation of GRB 200111A
  43. LIGO/Virgo S200114f: No counterpart in targeted WHT/ACAM imaging
  44. LIGO/Virgo S200115j: Revised list of possible host galaxies with the new skymap
  45. LIGO/Virgo S200114f: No Counterparts in DDOTI/OAN Optical Observations
  46. Fermi trigger No 600666048: Global MASTER-Net observations report
  47. IceCube-200107A: Upper limits from a search for additional neutrino events in IceCube
  48. IceCube Alert 200109.99: Global MASTER-Net observations report
  49. IceCube Alert 200109.99: Global MASTER-Net observations report
  50. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  51. GRB 200107B: Swift-XRT refined Analysis
  52. Fermi-LAT ANTARES coincidence
  53. Swift GRB 200107B: Global MASTER-Net observations report
  54. GRB 200107B: Swift-BAT refined analysis
  55. Fermi-LAT Gamma-ray Observations of IceCube-200107A
  56. IceCube-200107A: No significant detection in HAWC
  57. IceCube-200107A: No candidates from the Zwicky Transient Facility
  58. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  59. GRB 200107B: Swift detection of a burst
  60. IceCube-200107A: IceCube observation of a high-energy neutrino candidate event
  61. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  62. GRB 200105A: MAXI/GSC detection
  63. Fermi trigger No 599761015: Global MASTER-Net observations report
  64. IceCube Alert 200101.46: Global MASTER-Net observations report
  65. Fermi trigger No 599603971: Global MASTER-Net observations report
  66. IPN triangulation of GRB 191227B (short)
  67. GRB 191227A: Swift detection of a burst
  68. LIGO/Virgo S191205ah: MASTER OT detection
  69. LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
  70. LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
  71. LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
  72. LIGO/Virgo S191222n: upper limits from AGILE-GRID observations
  73. Baksan Neutrino Observatory Alert 191222.09: Global MASTER-Net observations report
  74. LIGO/Virgo S191216ap: MASTER optical observation
  75. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  76. Konus-Wind observation of GRB 191218A
  77. LIGO/Virgo S191213g: Lulin Follow-up Observations of AT2019wxt
  78. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  79. GRB 191218A: AstroSat CZTI detection
  80. GRB 191218A: Swift detection of a burst
  81. LIGO/Virgo S191216ap and IceCube neutrino: Swift XRT sources
  82. LIGO/Virgo S191215w: Coverage and upper limits from MAXI/GSC observations
  83. LIGO/Virgo S191215w: Global MASTER-Net observations report
  84. LIGO/Virgo S191213g: Upper limits from IceCube neutrino searches
  85. LIGO/Virgo S191212q: Global MASTER-Net observations report
  86. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  87. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  88. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  89. LIGO/Virgo S191204r: Identification of a GW compact binary merger candidate
  90. Fermi trigger No 596786686: Global MASTER-Net observations report
  91. Fermi trigger No 596808579: Global MASTER-Net observations report
  92. LIGO/Virgo S191129u: Identification of a GW compact binary merger candidate
  93. Baksan Neutrino Observatory Alert 191128.17: Global MASTER-Net observations report
  94. Fermi trigger No 596387570: Global MASTER-Net observations report
  95. Baksan Neutrino Observatory Alert 191124.13: Global MASTER-Net observations report
  96. LIGO/Virgo S191124be: Global MASTER-Net observations report
  97. Konus-Wind observation of the recent SGR 1935+2154 activity
  98. LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
  99. LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
  100. LIGO/Virgo S191109d: AstroSat CZTI upper limits

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