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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

3408 results found.

  1. GRB 200409A: Swift-XRT refined Analysis
  2. GRB 200405B: Swift-XRT observations
  3. GRB 200325B: further Swift-XRT observations
  4. GRB 200325B: Swift-XRT and UVOT observations
  5. GRB 200324A: Swift-XRT refined Analysis
  6. Chandra observations of GW170817 at 2.5 years since merger (All epochs 4 of 4)
  7. GW170817: Continued X-ray emission detected with Chandra at 940 days post-merger
  8. LIGO/Virgo S200316bj: No counterpart candidates in Fermi-LAT observations
  9. LIGO/Virgo S200213t: Continued Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  10. LIGO/Virgo S200311bg: No significant counterpart candidates in Fermi-LAT observations
  11. Chandra observations of GW170817 ~ 2.5 years since merger (epoch 1 of 4)
  12. GRB 200306C: Swift-XRT refined Analysis
  13. GRB 200306A: Swift-XRT refined Analysis
  14. GRB 200303A: Swift-XRT refined Analysis
  15. LIGO/Virgo S200302c: No significant counterpart candidates in Fermi-LAT observations
  16. GRB 200228B: Swift-XRT refined Analysis
  17. GRB 200227A: Swift-XRT refined Analysis
  18. LIGO/Virgo S200225q: No counterpart candidates in Fermi-LAT observations
  19. LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
  20. GRB 200219C: Swift-XRT afterglow confirmation
  21. GRB 200224A: Swift-XRT refined Analysis
  22. GRB 200219C: Swift-XRT afterglow detection
  23. LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  24. LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
  25. GRB 200219A: Swift-XRT refined Analysis correction
  26. GRB 200219A: Swift-XRT refined Analysis
  27. GRB 200216B: Swift-XRT refined Analysis
  28. Further Swift-XRT observations of Swift J0840.7-3516
  29. GRB 200215A: Swift-XRT refined Analysis
  30. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  31. LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
  32. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  33. GRB 200205B: ESO/NTT near-infrared imaging
  34. GRB 200205B: Swift-XRT refined Analysis
  35. GRB 200131A: Swift-XRT refined Analysis
  36. LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
  37. LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
  38. GRB 200127A: Swift-XRT refined Analysis
  39. GRB 200125A: Further Swift-XRT observations
  40. GRB 200125A: TNG detection of a NIR counterpart candidate
  41. Correction to GRB 200125A: Swift-XRT refined analysis
  42. GRB 200125A: Swift-XRT refined Analysis
  43. LIGO/Virgo S200115j: Further Swift-XRT sources
  44. GRB 200122A: Swift-XRT refined Analysis
  45. GRB 191031D: XMM-Newton upper limit
  46. LIGO/Virgo S200115j: NIR upper limits for ZTF20aafqvyc/AT2020yq from the Palomar 200-inch telescope
  47. LIGO/Virgo S200114f: No transients found in J-GEM observations of nearby galaxies
  48. LIGO/Virgo S200115j: Swift-XRT sources
  49. LIGO/Virgo S200114f: Swift-XRT sources and observations
  50. LIGO/Virgo S200115j: No counterpart candidates in Fermi-LAT observations
  51. LIGO/Virgo S200114f: No counterpart candidates in Fermi-LAT observations
  52. LIGO/Virgo 200112r: No counterpart candidates in Fermi-LAT observations
  53. GRB 200107B: Swift-XRT refined Analysis
  54. GRB 200109A: Swift-XRT refined Analysis
  55. LIGO/Virgo 200105ae: No counterpart candidates in Fermi-LAT observations
  56. Fermi trigger No 599954133: Global MASTER-Net observations report
  57. GRB 191228A: Swift-XRT refined Analysis
  58. GRB 191227A: Marginal detection by Fermi-LAT
  59. GRB 191221B: Swift-XRT refined Analysis
  60. LIGO/Virgo S191222n: No counterpart candidates in Fermi-LAT observations
  61. GRB 191220A: Swift-XRT refined Analysis
  62. LIGO/Virgo S191213g: Swift UVOT/XRT observations of Pan-STARRS1 candidate: PS19hgw
  63. LIGO/Virgo S191216ap: No candidates found in J-GEM follow-up observations of HAWC error region
  64. LIGO/Virgo S191213g: No candidates found in J-GEM follow-up observations
  65. LIGO/Virgo S191216ap and IceCube neutrino: Swift XRT sources
  66. LIGO/Virgo S191213g: Swift UVOT/XRT observations of three ZTF sources
  67. LIGO/Virgo G191216ap: No counterpart candidates in Fermi-LAT observations
  68. LIGO/Virgo S191215w: No counterpart candidates in Fermi-LAT observations
  69. LIGO/Virgo S191213g: No counterpart candidates in Fermi-LAT observations
  70. Possible HAWC-detected GRB 191210A: Fermi-LAT Upper Limits
  71. Possible HAWC-detected GRB 191210A: Swift-XRT observations
  72. Fermi trigger No 597737032: Global MASTER-Net observations report
  73. LIGO/Virgo S191205ah: No counterpart candidates in Fermi-LAT observations
  74. LIGO/Virgo S191204r: No counterpart candidates in Fermi-LAT observations
  75. GRB 191130A: Swift-XRT observations
  76. LIGO/Virgo S191129u: No counterpart candidates in Fermi-LAT observations
  77. GRB 191123A: Swift-XRT refined Analysis
  78. GRB 191122A: Swift-XRT refined Analysis
  79. LIGO/Virgo S191110af: Swift XRT observations, no secure afterglow found
  80. LIGO/Virgo S191110af: No counterpart candidates in Fermi-LAT observations
  81. LIGO/Virgo S191109d: No counterpart candidates in Fermi-LAT observations
  82. LIGO/Virgo S191105e: No counterpart candidates in Fermi-LAT observations
  83. GRB 191106A: Swift-XRT refined Analysis
  84. GRB 191101A: Swift-XRT refined Analysis
  85. GRB 191031C: Swift-XRT refined Analysis
  86. GRB 191031D: Swift-XRT refined Analysis
  87. GRB 191029A: CORRECTED Swift-XRT refined analysis
  88. GRB 191029A: Swift/UVOT Upper Limits
  89. GRB 191029A: Swift-XRT refined Analysis
  90. Swift Trigger 931384: possible GRB 191025A
  91. GRB 191024A: Swift-XRT refined Analysis
  92. GRB 191019A: Swift-XRT updated analysis
  93. GRB 191019A: Swift-XRT refined Analysis
  94. GRB 191017B: Swift-XRT refined Analysis
  95. GRB 191016A: Swift-XRT afterglow detection
  96. GRB 191016A: Swift/UVOT Detection
  97. GRB 191011A: Swift-XRT refined Analysis
  98. LIGO/Virgo S190930t: Continued Swift observations of AT2019sbk
  99. LIGO/Virgo S190930t: Swift XRT observations, no secure afterglow found
  100. GRB 191004B: Swift-XRT refined Analysis

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