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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"

28136 results found.

  1. GRB 250714A: SVOM/GRM observation
  2. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  3. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  4. GRB 250713A: Mephisto optical upper limits
  5. GRB 250713A: SVOM/VT optical upper limit
  6. GRB 250713A: NOT optical upper limits
  7. GRB 250713A: OHP/T193 upper limit
  8. GRB 250713A: SVOM/C-GFT upper limit
  9. GRB 250706B/C: 7DT Follow-up Observations
  10. GRB 250713A: Swift-XRT observations
  11. GRB 250713A: EP-FXT counterpart detection
  12. EP250711a: COLIBRÍ continuous optical observations
  13. GRB 250706A: Swift-BAT refined analysis
  14. GRB 250702F: Swift-BAT refined analysis
  15. GRB 250628A: Swift-BAT refined analysis
  16. LIGO/Virgo/KAGRA S250712cd: Updated Sky localization
  17. GRB 250713A: JinShan optical upper limits
  18. GRB 250713A: SVOM detection of a long burst
  19. EP250711a: Global MASTER-Net observations report
  20. GRB 250711A: DDOTI Optical Upper Limit
  21. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  22. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  23. GRB 250711A: SVOM/GRM observation
  24. EP250711a: NOT optical counterpart candidate
  25. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  26. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  27. GRB 250704A: GRANDMA observations
  28. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  29. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  30. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  31. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  32. IceCube-250708A: No Candidates from WINTER
  33. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  34. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  35. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  36. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  37. EP-WXT trigger 01709181970. confirmation of a stellar flare by BOOTES-6
  38. EP250704a/GRB 250704B: 10 GHz VLA detection
  39. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 4-Update Localization Volume
  40. IceCube-250706A: No Candidates from WINTER
  41. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  42. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  43. LIGO/Virgo/KAGRA S250705cb: Updated Sky localization
  44. LIGO/Virgo/KAGRA S250704ab: Updated Sky localization and EM Bright Classification
  45. LIGO/Virgo/KAGRA S250702n: Updated Sky localization
  46. LIGO/Virgo/KAGRA S250701bq: Updated Sky localization
  47. EP250704a/GRB250704B : HCT optical and NIR upper limits
  48. LIGO/Virgo/KAGRA S250701bp: Updated Sky localization
  49. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  50. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  51. GRB 250702F: radio detection with the VLA
  52. IceCube-250706A: EP-FXT follow-up observations
  53. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  54. GRB 250706B/C: Fermi-LAT detection
  55. IceCube-250706A: Global MASTER-Net observations report
  56. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  57. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  58. GRB 250706B: Swift/UVOT Detection
  59. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  60. GRB 250702F: GRANDMA observations
  61. GRB 250706A: Swift-XRT refined Analysis
  62. GRB 250706B: refined SVOM/MXT data analysis
  63. GRB 250706A: Swift/UVOT Upper Limits
  64. GRB 250706B: REM optical observations
  65. GRB 250706A: REM optical/NIR observations
  66. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  67. IceCube-250416A: DDOTI Optical Upper Limit
  68. IceCube-250706A: COLIBRÍ optical upper limits
  69. GRB 250706A: JinShan optical upper limits
  70. GRB 250706A: SAO RAS optical observations
  71. EP250704A: NOWT Detection
  72. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  73. GRB250706B: Swift-XRT counterpart detection
  74. GRB 250706B: iTelescope optical observations
  75. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  76. GRB 250706B: SVOM/VT optical observation
  77. GRB 250706B: TRT bright optical counterpart detection
  78. GRB 250706A: GROWTH-India Telescope optical upper limit
  79. GRB 250706B: SVOM detection of a long burst
  80. GRB 250706A: Swift detection of a burst
  81. GRB 250704B: Swift-XRT refined Analysis
  82. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  83. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart
  84. GRB 250703A: EIRSAT-1 GMOD Detection
  85. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  86. GRB 250704B: Swift/UVOT Upper Limits
  87. GRB 250704A: Swift/UVOT Detection
  88. LIGO/Virgo/KAGRA S250705cb: Identification of a GW compact binary merger candidate
  89. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  90. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  91. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  92. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  93. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  94. GRB 250702F: Kilonova-Catcher optical afterglow detection
  95. GRB 250702F: Monte Agliale Observatory optical observations
  96. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  97. EP250704a / GRB 250704B: JinShan optical observations
  98. EP250704a / GRB 250704B: SAO RAS optical observations
  99. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  100. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 3-Initial Localization Volume

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