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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"

3110 results found.

  1. Fermi trigger No 606918292: Global MASTER-Net observations report
  2. GRB 200326A: Fermi GBM Final Real-time Localization
  3. Fermi trigger No 606681997: Global MASTER-Net observations report
  4. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  5. Fermi trigger No 606263732: Global MASTER-Net observations report
  6. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  7. LIGO/Virgo S200316bj: Upper limits from Insight-HXMT/HE observations
  8. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  9. LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
  10. LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations
  11. SGR Swift J1818.0-1607: BOOTES-4/MET optical limit
  12. Fermi trigger No 605756501: Global MASTER-Net observations report
  13. Swift-BAT trigger 960986: Swift detection of a new SGR Swift J1818.0-1607
  14. Fermi trigger No 605632577: Global MASTER-Net observations report
  15. GRB 200310A: MAXI/GSC detection
  16. LIGO/Virgo S200302c : No significant candidates in FRAM - TAROT - GRANDMA observations.
  17. GRB 200303A: Fermi GBM Final Real-time Localization
  18. LIGO/Virgo S200302c: No counterpart candidates in KAIT observations
  19. LIGO/Virgo S200302c: no counterpart candidates in the Swift/BAT observations
  20. LIGO/Virgo S200224ca: Transient found in Swift/UVOT counterpart search
  21. LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
  22. LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
  23. GRB 200227A: Mondy optical upper limit
  24. LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
  25. LIGO/Virgo S200224car: GRAWITA VST-ESO PARANAL observations.
  26. LIGO/Virgo S200225q: no counterpart candidates in the Swift/BAT observations
  27. LIGO/Virgo S200224ca: no counterpart candidates in the Swift/BAT observations
  28. GRB 200224B: DDOTI/OAN optical observations report
  29. LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
  30. LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
  31. Fermi trigger No 604231129: Global MASTER-Net observations report
  32. GRB 200224C: Fermi GBM Final Real-time Localization
  33. GRB 200223A: Fermi GBM Final Real-time Localization
  34. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  35. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  36. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  37. LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
  38. GRB 200216B: Mondy and AbAO optical upper limits
  39. LIGO/Virgo S200213t: No EM counterparts found from continued GECKO observation of host galaxy candidates
  40. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  41. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  42. LIGO/Virgo S200213t: One additional candidate from the Zwicky Transient Facility
  43. LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
  44. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  45. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  46. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  47. LIGO/Virgo S200213t: Candidates from the Zwicky Transient Facility
  48. LIGO/Virgo trigger S200213t: Possible host galaxies
  49. GRB 200131A: Tautenburg observations
  50. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  51. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  52. LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
  53. Fermi trigger No 602817262: Global MASTER-Net observations report
  54. GRB 200205B: Swift-BAT refined analysis
  55. Fermi trigger No 602731380: Global MASTER-Net observations report
  56. Fermi trigger No 602626648: Global MASTER-Net observations report
  57. GRB 200205C: Fermi GBM Final Real-time Localization
  58. ZTF20aajnksq: Occulted by Earth at the time of GRB 200128A
  59. ZTF Discovery of ZTF20aajnksq: a Rapidly Fading Luminous Transient in the GRB 200128A Localiziation Region
  60. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  61. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  62. Fermi trigger No 602071201: Global MASTER-Net observations report
  63. Fermi trigger No 602056641: Global MASTER-Net observations report
  64. LIGO/Virgo S200129m: no counterpart candidates in the Swift/BAT observations
  65. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  66. LIGO/Virgo S200128d: no counterpart candidates in the Swift/BAT observations
  67. GRB 200125B: DDOTI/OAN optical observations report
  68. Fermi trigger No 601841483: Global MASTER-Net observations report
  69. Fermi trigger No 601729856: Global MASTER-Net observations report
  70. Fermi trigger No 601677816: Global MASTER-Net observations report
  71. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  72. GRB 200122A: MITSuME Akeno optical upper limits
  73. Fermi trigger No 601363105: Global MASTER-Net observations report
  74. Konus-Wind observation of GRB 200120A
  75. Fermi trigger No 601254300: Global MASTER-Net observations report
  76. IceCube Alert 200120.78: Global MASTER-Net observations report
  77. LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
  78. IceCube-200117A: One Additional Candidate Counterpart from the Zwicky Transient Facility
  79. IceCube-200117A: Candidate Counterpart from the Zwicky Transient Facility
  80. LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
  81. LIGO/Virgo S200114f: More candidates from the Zwicky Transient Facility
  82. LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
  83. LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
  84. LIGO/Virgo S200115j: no counterpart candidates in the Swift/BAT observations
  85. LIGO/Virgo S200115j: Candidates from the Zwicky Transient Facility
  86. LIGO/Virgo trigger S200115j: Possible host galaxies
  87. LIGO/Virgo S200114f: no counterpart candidates in the Swift/BAT observations
  88. IceCube-200109A: Candidate Counterparts from the Zwicky Transient Facility
  89. LIGO/Virgo S200114f: Candidates from the Zwicky Transient Facility
  90. LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
  91. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  92. Fermi trigger No 600227156: Global MASTER-Net observations report
  93. Swift GRB200109.07: Global MASTER-Net observations report
  94. GRB 200109A: Swift detection of a burst
  95. LIGO/Virgo S200105ae: Candidates from the Zwicky Transient Facility
  96. GRB 200107B: Fermi GBM observation
  97. IceCube-200107A: No candidates from the Zwicky Transient Facility
  98. LIGO/Virgo S200105ae: Upper Limits from the Zwicky Transient Facility
  99. LIGO/Virgo S200105ae: no counterpart candidates in the Swift/BAT observations
  100. LIGO/Virgo S200105ae: Global MASTER-Net observations report

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