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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"

3039 results found.

  1. IceCube-200512A: No Candidate Counterparts from the Zwicky Transient Facility
  2. Konus-Wind observation of SGR 1935+2154 activity on 2020 May 10
  3. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  4. Insight-HXMT X-ray and hard X-ray upper limits to the radio burst detected by FAST from SGR 1935+2154
  5. Fermi GBM trigger 200429866/609886052 is not a GRB
  6. Konus-Wind observation of hard X-ray counterpart of the radio burst from SGR 1935+2154
  7. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  8. IceCube-200425A: No significant detection in HAWC
  9. GRB 200423A: Fermi GBM Final Real-time Localization
  10. Fermi GRB 200421A: Global MASTER-Net observations report
  11. GRB 200421A: Fermi GBM Final Real-time Localization
  12. Fermi trigger No 608935505: Global MASTER-Net observations report
  13. GRB 200415A: MASTER imspection and possible localisation
  14. GRB 200416A: Swift detection of a burst with an optical afterglow
  15. Konus-Wind observation of GRB 200412A
  16. Baksan Neutrino Observatory Alert 200408.26: Global MASTER-Net observations report
  17. Swift GRB 200409A: Global MASTER-Net observations report
  18. Fermi GRB 200407A: Global MASTER-Net observations report
  19. Baksan Neutrino Observatory Alert 200406.3: Global MASTER-Net observations report
  20. Fermi GRB 200405A: Global MASTER-Net observations report
  21. Fermi GRB 200403B: Global MASTER-Net observations report
  22. Fermi GRB 200403A: Global MASTER-Net observations report
  23. Fermi GRB 200402C: Global MASTER-Net observations report
  24. Fermi GRB 200401A: Global MASTER-Net observations report
  25. GRB 200325B: Mondy continued observations
  26. Fermi trigger No 606918292: Global MASTER-Net observations report
  27. GRB 200326A: Fermi GBM Final Real-time Localization
  28. Fermi trigger No 606681997: Global MASTER-Net observations report
  29. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  30. Fermi trigger No 606263732: Global MASTER-Net observations report
  31. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  32. LIGO/Virgo S200316bj: Upper limits from Insight-HXMT/HE observations
  33. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  34. LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
  35. LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations
  36. SGR Swift J1818.0-1607: BOOTES-4/MET optical limit
  37. Fermi trigger No 605756501: Global MASTER-Net observations report
  38. Swift-BAT trigger 960986: Swift detection of a new SGR Swift J1818.0-1607
  39. Fermi trigger No 605632577: Global MASTER-Net observations report
  40. GRB 200310A: MAXI/GSC detection
  41. LIGO/Virgo S200302c : No significant candidates in FRAM - TAROT - GRANDMA observations.
  42. GRB 200303A: Fermi GBM Final Real-time Localization
  43. LIGO/Virgo S200302c: No counterpart candidates in KAIT observations
  44. LIGO/Virgo S200302c: no counterpart candidates in the Swift/BAT observations
  45. LIGO/Virgo S200224ca: Transient found in Swift/UVOT counterpart search
  46. LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
  47. LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
  48. GRB 200227A: Mondy optical upper limit
  49. LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
  50. LIGO/Virgo S200224car: GRAWITA VST-ESO PARANAL observations.
  51. LIGO/Virgo S200225q: no counterpart candidates in the Swift/BAT observations
  52. LIGO/Virgo S200224ca: no counterpart candidates in the Swift/BAT observations
  53. GRB 200224B: DDOTI/OAN optical observations report
  54. LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
  55. LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
  56. Fermi trigger No 604231129: Global MASTER-Net observations report
  57. GRB 200224C: Fermi GBM Final Real-time Localization
  58. GRB 200223A: Fermi GBM Final Real-time Localization
  59. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  60. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  61. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  62. LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
  63. GRB 200216B: Mondy and AbAO optical upper limits
  64. LIGO/Virgo S200213t: No EM counterparts found from continued GECKO observation of host galaxy candidates
  65. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  66. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  67. LIGO/Virgo S200213t: One additional candidate from the Zwicky Transient Facility
  68. LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
  69. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  70. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  71. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  72. LIGO/Virgo S200213t: Candidates from the Zwicky Transient Facility
  73. LIGO/Virgo trigger S200213t: Possible host galaxies
  74. GRB 200131A: Tautenburg observations
  75. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  76. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  77. LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
  78. Fermi trigger No 602817262: Global MASTER-Net observations report
  79. GRB 200205B: Swift-BAT refined analysis
  80. Fermi trigger No 602731380: Global MASTER-Net observations report
  81. Fermi trigger No 602626648: Global MASTER-Net observations report
  82. GRB 200205C: Fermi GBM Final Real-time Localization
  83. ZTF20aajnksq: Occulted by Earth at the time of GRB 200128A
  84. ZTF Discovery of ZTF20aajnksq: a Rapidly Fading Luminous Transient in the GRB 200128A Localiziation Region
  85. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  86. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  87. Fermi trigger No 602071201: Global MASTER-Net observations report
  88. Fermi trigger No 602056641: Global MASTER-Net observations report
  89. LIGO/Virgo S200129m: no counterpart candidates in the Swift/BAT observations
  90. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  91. LIGO/Virgo S200128d: no counterpart candidates in the Swift/BAT observations
  92. GRB 200125B: DDOTI/OAN optical observations report
  93. Fermi trigger No 601841483: Global MASTER-Net observations report
  94. Fermi trigger No 601729856: Global MASTER-Net observations report
  95. Fermi trigger No 601677816: Global MASTER-Net observations report
  96. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  97. GRB 200122A: MITSuME Akeno optical upper limits
  98. Fermi trigger No 601363105: Global MASTER-Net observations report
  99. Konus-Wind observation of GRB 200120A
  100. Fermi trigger No 601254300: Global MASTER-Net observations report

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