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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"

26689 results found.

  1. GRB 250713A: SVOM/C-GFT upper limit
  2. GRB 250706B/C: 7DT Follow-up Observations
  3. GRB 250713A: Swift-XRT observations
  4. GRB 250713A: EP-FXT counterpart detection
  5. EP250711a: COLIBRÍ continuous optical observations
  6. GRB 250706A: Swift-BAT refined analysis
  7. GRB 250713A: JinShan optical upper limits
  8. GRB 250713A: SVOM detection of a long burst
  9. GRB 250711A: DDOTI Optical Upper Limit
  10. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  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. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  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. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  24. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  25. IceCube-250708A: No Candidates from WINTER
  26. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  27. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  28. EP-WXT trigger 01709181970. confirmation of a stellar flare by BOOTES-6
  29. EP250704a/GRB 250704B: 10 GHz VLA detection
  30. The EP-WXT trigger 01709181970 is likely a flaring star
  31. IceCube-250706A: No Candidates from WINTER
  32. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  33. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  34. LIGO/Virgo/KAGRA S250704ab: Updated Sky localization and EM Bright Classification
  35. EP250704a/GRB250704B : HCT optical and NIR upper limits
  36. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  37. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  38. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  39. GRB 250702F: radio detection with the VLA
  40. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  41. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  42. GRB 250706B/C: Fermi-LAT detection
  43. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  44. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  45. GRB 250706B: Swift/UVOT Detection
  46. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  47. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  48. GRB 250702F: GRANDMA observations
  49. GRB 250706A: Swift-XRT refined Analysis
  50. GRB 250706B: refined SVOM/MXT data analysis
  51. GRB 250706A: Swift/UVOT Upper Limits
  52. GRB 250706B: REM optical observations
  53. GRB 250706A: REM optical/NIR observations
  54. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  55. IceCube-250416A: DDOTI Optical Upper Limit
  56. IceCube-250706A: COLIBRÍ optical upper limits
  57. GRB 250706A: JinShan optical upper limits
  58. GRB 250706A: SAO RAS optical observations
  59. EP250704A: NOWT Detection
  60. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  61. The EP-WXT trigger 01709181580 is likely a flaring star
  62. GRB250706B: Swift-XRT counterpart detection
  63. GRB 250706B: iTelescope optical observations
  64. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  65. GRB 250706B: SVOM/VT optical observation
  66. GRB 250706B: TRT bright optical counterpart detection
  67. GRB 250706A: GROWTH-India Telescope optical upper limit
  68. GRB 250706B: SVOM detection of a long burst
  69. GRB 250706A: Swift detection of a burst
  70. GRB 250704B: Swift-XRT refined Analysis
  71. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  72. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart
  73. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  74. GRB 250704B: Swift/UVOT Upper Limits
  75. GRB 250704A: Swift/UVOT Detection
  76. LIGO/Virgo/KAGRA S250705cb: Identification of a GW compact binary merger candidate
  77. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  78. Konus-Wind detection of GRB 250703A
  79. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  80. Konus-Wind detection of short/hard GRB 250704B/ EP250704a
  81. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  82. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  83. GRB 250702F: Kilonova-Catcher optical afterglow detection
  84. GRB 250702F: Monte Agliale Observatory optical observations
  85. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  86. EP250704a / GRB 250704B: JinShan optical observations
  87. EP250704a / GRB 250704B: SAO RAS optical observations
  88. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  89. EP250704a: refined analysis of the EP-WXT and FXT follow-up observations
  90. LIGO/Virgo/KAGRA S250704ab: Upper limits from Fermi-GBM Observations
  91. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  92. EP250704a / GRB250704B: Swift-XRT counterpart detection
  93. GRB 250704A: Swift-XRT afterglow detection
  94. Konus-Wind detection of GRB 250702F
  95. EP250704a / GRB 250704B - REM observations
  96. GRB 250702F: GROWTH-India Telescope optical observations
  97. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection
  98. GRB 250704A: REM retraction of optical afterglow detection and updated limit
  99. EP250702a: WFST optical observations
  100. EP250704a: COLIBRÍ optical counterpart candidate

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