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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"

3139 results found.

  1. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  2. GRB 200219B: Fermi GBM Final Real-time Localization
  3. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  4. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  5. LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
  6. LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
  7. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  8. LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy
  9. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  10. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  11. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  12. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  13. LIGO/Virgo S200208q: Global MASTER-Net observations report
  14. Fermi trigger No 602817262: Global MASTER-Net observations report
  15. MAXI GRB200205.29: Global MASTER-Net observations report
  16. GRB 200131A: Swift detection of a burst with an optical counterpart
  17. Swift GRB200131.95: Global MASTER-Net observations report
  18. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  19. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  20. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  21. LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  22. GRB 200125A: Swift-BAT refined analysis
  23. GRB 200127A: Swift detection of a burst
  24. Fermi trigger No 601729856: Global MASTER-Net observations report
  25. Fermi trigger No 601677816: Global MASTER-Net observations report
  26. GRB 200125B: Fermi GBM Final Real-time Localization
  27. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  28. Fermi trigger No 601363105: Global MASTER-Net observations report
  29. GRB 200122A: Swift detection of a burst
  30. GRB 200120A: Fermi GBM Final Real-time Localization
  31. LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
  32. LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
  33. GRB 200115A: AROMA-N Optical Observation
  34. LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
  35. LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
  36. Baksan Neutrino Observatory Alert 200116.21: Global MASTER-Net observations report
  37. IPN triangulation of GRB 200111A
  38. LIGO/Virgo S200114f: No counterpart in targeted WHT/ACAM imaging
  39. LIGO/Virgo S200115j: Revised list of possible host galaxies with the new skymap
  40. LIGO/Virgo S200114f: No Counterparts in DDOTI/OAN Optical Observations
  41. Fermi trigger No 600666048: Global MASTER-Net observations report
  42. IceCube-200107A: Upper limits from a search for additional neutrino events in IceCube
  43. IceCube Alert 200109.99: Global MASTER-Net observations report
  44. IceCube Alert 200109.99: Global MASTER-Net observations report
  45. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  46. GRB 200107B: Swift-XRT refined Analysis
  47. Fermi-LAT ANTARES coincidence
  48. Swift GRB 200107B: Global MASTER-Net observations report
  49. GRB 200107B: Swift-BAT refined analysis
  50. Fermi-LAT Gamma-ray Observations of IceCube-200107A
  51. IceCube-200107A: No significant detection in HAWC
  52. IceCube-200107A: No candidates from the Zwicky Transient Facility
  53. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  54. GRB 200107B: Swift detection of a burst
  55. IceCube-200107A: IceCube observation of a high-energy neutrino candidate event
  56. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  57. GRB 200105A: MAXI/GSC detection
  58. Fermi trigger No 599761015: Global MASTER-Net observations report
  59. IceCube Alert 200101.46: Global MASTER-Net observations report
  60. Fermi trigger No 599603971: Global MASTER-Net observations report
  61. IPN triangulation of GRB 191227B (short)
  62. GRB 191227A: Swift detection of a burst
  63. LIGO/Virgo S191205ah: MASTER OT detection
  64. LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
  65. LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
  66. LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
  67. LIGO/Virgo S191222n: upper limits from AGILE-GRID observations
  68. Baksan Neutrino Observatory Alert 191222.09: Global MASTER-Net observations report
  69. LIGO/Virgo S191216ap: MASTER optical observation
  70. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  71. Konus-Wind observation of GRB 191218A
  72. LIGO/Virgo S191213g: Lulin Follow-up Observations of AT2019wxt
  73. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  74. GRB 191218A: AstroSat CZTI detection
  75. GRB 191218A: Swift detection of a burst
  76. LIGO/Virgo S191216ap and IceCube neutrino: Swift XRT sources
  77. LIGO/Virgo S191215w: Coverage and upper limits from MAXI/GSC observations
  78. LIGO/Virgo S191215w: Global MASTER-Net observations report
  79. LIGO/Virgo S191213g: Upper limits from IceCube neutrino searches
  80. LIGO/Virgo S191212q: Global MASTER-Net observations report
  81. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  82. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  83. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  84. LIGO/Virgo S191204r: Identification of a GW compact binary merger candidate
  85. Fermi trigger No 596786686: Global MASTER-Net observations report
  86. Fermi trigger No 596808579: Global MASTER-Net observations report
  87. LIGO/Virgo S191129u: Identification of a GW compact binary merger candidate
  88. Baksan Neutrino Observatory Alert 191128.17: Global MASTER-Net observations report
  89. Fermi trigger No 596387570: Global MASTER-Net observations report
  90. Baksan Neutrino Observatory Alert 191124.13: Global MASTER-Net observations report
  91. LIGO/Virgo S191124be: Global MASTER-Net observations report
  92. Konus-Wind observation of the recent SGR 1935+2154 activity
  93. LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
  94. LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
  95. LIGO/Virgo S191109d: AstroSat CZTI upper limits
  96. GRB 191031D: Chandra upper limit
  97. Fermi trigger No 594592184: Global MASTER-Net observations report
  98. Fermi trigger No 594557071: Global MASTER-Net observations report
  99. Baksan Neutrino Observatory Alert 191102.06: Global MASTER-Net observations report
  100. Swift GRB191031.89: Global MASTER-Net observations report

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