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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"

32688 results found.

  1. EP250711a: COLIBRÍ continuous optical observations
  2. GRB 250706A: Swift-BAT refined analysis
  3. GRB 250702F: Swift-BAT refined analysis
  4. GRB 250628A: Swift-BAT refined analysis
  5. LIGO/Virgo/KAGRA S250712cd: Updated Sky localization
  6. GRB 250713A: JinShan optical upper limits
  7. EP250711a: Global MASTER-Net observations report
  8. GRB 250711A: DDOTI Optical Upper Limit
  9. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  10. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate (duplicate submission)
  11. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  12. GRB 250711A: SVOM/GRM observation
  13. EP250711a: NOT optical counterpart candidate
  14. EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  15. Fermi GRB 250711A: Global MASTER-Net observations report
  16. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  17. GRB 250704A: GRANDMA observations
  18. GRB 250704A: SVOM/ECLAIRs refined analysis
  19. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  20. GRB 250702B,D,E/EP250702A: JCMT sub-mm observations at 350 GHz
  21. GRB 250704B / EP250704a: 1.3 GHz MeerKAT Detection
  22. GRB 250702B,D,E / EP250702a: ALMA detection
  23. IceCube-250708A: No Candidates from WINTER
  24. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  25. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  26. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  27. IPN triangulation of GRB 250704B (short/hard, consistent with EP 250704a)
  28. GRB 250706B/C: Insight-HXMT detection
  29. EP/WXT 01709181970: GOTO observations confirm stellar variability
  30. EP250704a/GRB 250704B: 10 GHz VLA detection
  31. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  32. IceCube-250706A: No Candidates from WINTER
  33. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  34. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  35. GRB 250704B / EP250704a: VLA radio detection
  36. Fermi GRB 250708A: Global MASTER-Net observations report
  37. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  38. LIGO/Virgo/KAGRA S250705cb: Updated Sky localization
  39. LIGO/Virgo/KAGRA S250704ab: Updated Sky localization and EM Bright Classification
  40. LIGO/Virgo/KAGRA S250702n: Updated Sky localization
  41. LIGO/Virgo/KAGRA S250701bq: Updated Sky localization
  42. EP250704a/GRB250704B : HCT optical and NIR upper limits
  43. LIGO/Virgo/KAGRA S250701bp: Updated Sky localization
  44. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  45. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  46. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  47. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  48. GRB 250702F: radio detection with the VLA
  49. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  50. IceCube-250706A: EP-FXT follow-up observations
  51. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  52. GRB 250706B/C: Fermi-LAT detection
  53. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  54. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  55. GRB 250706B: Swift/UVOT Detection
  56. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  57. GRB 250706C: Konus-Wind detection of a very bright GRB ~1200 s before GRB 250706B
  58. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  59. GRB 250702F: GRANDMA observations
  60. GRB 250706B: refined SVOM/MXT data analysis
  61. GRB 250706A: Swift/UVOT Upper Limits
  62. GRB 250706B: REM optical observations
  63. GRB 250706A: REM optical/NIR observations
  64. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  65. IceCube-250416A: DDOTI Optical Upper Limit
  66. IceCube-250706A: COLIBRÍ optical upper limits
  67. Swift GRB 250706A: Global MASTER-Net observations report
  68. GRB 250706A: JinShan optical upper limits
  69. GRB 250706A: SAO RAS optical observations
  70. EP250704A: NOWT Detection
  71. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  72. GRB250706B: Swift-XRT counterpart detection
  73. GRB 250706B: iTelescope optical observations
  74. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  75. GRB 250706B: SVOM/VT optical observation
  76. GRB 250706B: TRT bright optical counterpart detection
  77. GRB 250706A: GROWTH-India Telescope optical upper limit
  78. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  79. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart
  80. GRB 250703A: EIRSAT-1 GMOD Detection
  81. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  82. GRB 250704B: Swift/UVOT Upper Limits
  83. GRB 250704A: Swift/UVOT Detection
  84. LIGO/Virgo/KAGRA S250705cb: Identification of a GW compact binary merger candidate
  85. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  86. GRB 250704B: Insight-HXMT detection
  87. Konus-Wind detection of GRB 250703A
  88. IPN triangulation of GRB 250703A
  89. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  90. EP250704a/GRB 250704B: FTW optical and NIR observations of the counterpart
  91. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  92. Konus-Wind detection of short/hard GRB 250704B/ EP250704a
  93. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  94. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  95. GRB 250702F: Kilonova-Catcher optical afterglow detection
  96. GRB 250702F: Monte Agliale Observatory optical observations
  97. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  98. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  99. EP250704a / GRB 250704B: JinShan optical observations
  100. GRB 250704A: SVOM/VT optical observation

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