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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"

20405 results found.

  1. GRB 250713A: Mephisto optical upper limits
  2. GRB 250713A: SVOM/VT optical upper limit
  3. GRB 250713A: NOT optical upper limits
  4. GRB 250713A: OHP/T193 upper limit
  5. GRB 250713A: SVOM/C-GFT upper limit
  6. GRB 250706B/C: 7DT Follow-up Observations
  7. GRB 250713A: EP-FXT counterpart detection
  8. EP250711a: COLIBRÍ continuous optical observations
  9. GRB 250713A: JinShan optical upper limits
  10. GRB 250713A: SVOM detection of a long burst
  11. GRB 250711A: DDOTI Optical Upper Limit
  12. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  13. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  14. GRB 250711A: SVOM/GRM observation
  15. EP250711a: NOT optical counterpart candidate
  16. EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  17. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  18. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  19. GRB 250704A: GRANDMA observations
  20. GRB 250704A: SVOM/ECLAIRs refined analysis
  21. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  22. GRB 250702B,D,E/EP250702A: JCMT sub-mm observations at 350 GHz
  23. IceCube-250708A: No Candidates from WINTER
  24. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  25. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  26. IPN triangulation of GRB 250704B (short/hard, consistent with EP 250704a)
  27. EP250704a/GRB 250704B: 10 GHz VLA detection
  28. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 4-Update Localization Volume
  29. IceCube-250706A: No Candidates from WINTER
  30. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  31. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  32. EP250704a/GRB250704B : HCT optical and NIR upper limits
  33. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  34. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  35. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  36. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  37. GRB 250702F: radio detection with the VLA
  38. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  39. GRB 250706B/C: Fermi-LAT detection
  40. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  41. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  42. GRB 250706B: Swift/UVOT Detection
  43. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  44. GRB 250702F: GRANDMA observations
  45. GRB 250706A: Swift/UVOT Upper Limits
  46. GRB 250706B: REM optical observations
  47. GRB 250706A: REM optical/NIR observations
  48. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  49. IceCube-250416A: DDOTI Optical Upper Limit
  50. IceCube-250706A: COLIBRÍ optical upper limits
  51. GRB 250706A: JinShan optical upper limits
  52. GRB 250706A: SAO RAS optical observations
  53. EP250704A: NOWT Detection
  54. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  55. GRB 250706B: iTelescope optical observations
  56. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  57. GRB 250706B: SVOM/VT optical observation
  58. GRB 250706B: TRT bright optical counterpart detection
  59. GRB 250706A: GROWTH-India Telescope optical upper limit
  60. GRB 250706B: SVOM detection of a long burst
  61. GRB 250706A: Swift detection of a burst
  62. GRB 250704B: Swift-XRT refined Analysis
  63. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  64. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart
  65. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  66. GRB 250704B: Swift/UVOT Upper Limits
  67. GRB 250704A: Swift/UVOT Detection
  68. LIGO/Virgo/KAGRA S250705cb: Identification of a GW compact binary merger candidate
  69. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  70. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  71. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  72. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  73. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  74. GRB 250702F: Kilonova-Catcher optical afterglow detection
  75. GRB 250702F: Monte Agliale Observatory optical observations
  76. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  77. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  78. EP250704a / GRB 250704B: JinShan optical observations
  79. EP250704a / GRB 250704B: SAO RAS optical observations
  80. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  81. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  82. EP250704a / GRB 250704B: Pan-STARRS iz-band imaging and photometry
  83. EP 250704a: BOOTES-5 optical detection
  84. EP250704a: refined analysis of the EP-WXT and FXT follow-up observations
  85. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  86. GRB 250704A: Swift-XRT afterglow detection
  87. EP250704a / GRB 250704B - REM observations
  88. GRB 250702F: GROWTH-India Telescope optical observations
  89. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection
  90. GRB 250704A: REM retraction of optical afterglow detection and updated limit
  91. EP250702a: WFST optical observations
  92. EP250704a: COLIBRÍ optical counterpart candidate
  93. EP250704a: Einstein Probe detection of an X-ray transient
  94. GRB 250704A: REM detection of the optical afterglow
  95. LIGO/Virgo/KAGRA S250704ab: Identification of a GW compact binary merger candidate
  96. GRB 250704A: SVOM detection of a burst
  97. GRB 250702F: Swift/UVOT Detection
  98. GRB 250702F: Leavitt Observatory optical observations
  99. GRB 250702F: AKO Optical Afterglow Detection
  100. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate

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