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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"

32764 results found.

  1. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  2. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  3. IPN triangulation of GRB 250704B (short/hard, consistent with EP 250704a)
  4. GRB 250706B/C: Insight-HXMT detection
  5. EP/WXT 01709181970: GOTO observations confirm stellar variability
  6. EP250704a/GRB 250704B: 10 GHz VLA detection
  7. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  8. IceCube-250706A: No Candidates from WINTER
  9. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  10. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  11. GRB 250704B / EP250704a: VLA radio detection
  12. Fermi GRB 250708A: Global MASTER-Net observations report
  13. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  14. LIGO/Virgo/KAGRA S250705cb: Updated Sky localization
  15. LIGO/Virgo/KAGRA S250704ab: Updated Sky localization and EM Bright Classification
  16. LIGO/Virgo/KAGRA S250702n: Updated Sky localization
  17. LIGO/Virgo/KAGRA S250701bq: Updated Sky localization
  18. EP250704a/GRB250704B : HCT optical and NIR upper limits
  19. LIGO/Virgo/KAGRA S250701bp: Updated Sky localization
  20. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  21. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  22. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  23. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  24. GRB 250702F: radio detection with the VLA
  25. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  26. IceCube-250706A: EP-FXT follow-up observations
  27. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  28. GRB 250706B/C: Fermi-LAT detection
  29. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  30. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  31. GRB 250706B: Swift/UVOT Detection
  32. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  33. GRB 250706C: Konus-Wind detection of a very bright GRB ~1200 s before GRB 250706B
  34. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  35. GRB 250702F: GRANDMA observations
  36. GRB 250706B: refined SVOM/MXT data analysis
  37. GRB 250706A: Swift/UVOT Upper Limits
  38. GRB 250706B: REM optical observations
  39. GRB 250706A: REM optical/NIR observations
  40. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  41. IceCube-250416A: DDOTI Optical Upper Limit
  42. IceCube-250706A: COLIBRÍ optical upper limits
  43. Swift GRB 250706A: Global MASTER-Net observations report
  44. GRB 250706A: JinShan optical upper limits
  45. GRB 250706A: SAO RAS optical observations
  46. EP250704A: NOWT Detection
  47. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  48. GRB250706B: Swift-XRT counterpart detection
  49. GRB 250706B: iTelescope optical observations
  50. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  51. GRB 250706B: SVOM/VT optical observation
  52. GRB 250706B: TRT bright optical counterpart detection
  53. GRB 250706A: GROWTH-India Telescope optical upper limit
  54. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  55. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart
  56. GRB 250703A: EIRSAT-1 GMOD Detection
  57. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  58. GRB 250704B: Swift/UVOT Upper Limits
  59. GRB 250704A: Swift/UVOT Detection
  60. LIGO/Virgo/KAGRA S250705cb: Identification of a GW compact binary merger candidate
  61. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  62. GRB 250704B: Insight-HXMT detection
  63. Konus-Wind detection of GRB 250703A
  64. IPN triangulation of GRB 250703A
  65. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  66. EP250704a/GRB 250704B: FTW optical and NIR observations of the counterpart
  67. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  68. Konus-Wind detection of short/hard GRB 250704B/ EP250704a
  69. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  70. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  71. GRB 250702F: Kilonova-Catcher optical afterglow detection
  72. GRB 250702F: Monte Agliale Observatory optical observations
  73. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  74. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  75. EP250704a / GRB 250704B: JinShan optical observations
  76. GRB 250704A: SVOM/VT optical observation
  77. EP250704a / GRB 250704B: SAO RAS optical observations
  78. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  79. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  80. EP250704a / GRB 250704B: SVOM/VT optical blue counterpart
  81. EP250704a / GRB 250704B: Pan-STARRS iz-band imaging and photometry
  82. EP 250704a: BOOTES-5 optical detection
  83. EP250704a: refined analysis of the EP-WXT and FXT follow-up observations
  84. LIGO/Virgo/KAGRA S250704ab: Upper limits from Fermi-GBM Observations
  85. GRB 250702A: Insight-HXMT detection
  86. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  87. GRBs 250702B/C/D/E / EP250702a: Swift/UVOT Upper Limits
  88. EP250704a / GRB250704B: Swift-XRT counterpart detection
  89. GRB 250704A: Swift-XRT afterglow detection
  90. GRB 250702B / EP2050702a: FTW optical and NIR observations
  91. Konus-Wind detection of GRB 250702F
  92. EP250704a / GRB 250704B - REM observations
  93. GRB 250702F: GROWTH-India Telescope optical observations
  94. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection
  95. GRB 250704A: REM retraction of optical afterglow detection and updated limit
  96. EP250702a: WFST optical observations
  97. EP250704a: COLIBRÍ optical counterpart candidate
  98. EP250704a: Einstein Probe detection of an X-ray transient
  99. GRB 250702F: optical photometry from Konkoly
  100. GRB 250704A: REM detection of the optical afterglow

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