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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"

20516 results found.

  1. GRB 250713A : SVOM/ECLAIRs refined analysis
  2. GRB 250717B: SVOM/GRM observation
  3. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  4. GRB 250717B: COLIBRÍ optical upper limit
  5. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  6. GRB 270713A: Kitab and AbAO Optical Observations
  7. Konus-Wind detection of GRB 250716A
  8. GRB 250716A: Swift-XRT afterglow detection
  9. GRB 250714A: SVOM/GRM observation
  10. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  11. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  12. GRB 250713A: Mephisto optical upper limits
  13. GRB 250713A: SVOM/VT optical upper limit
  14. GRB 250713A: NOT optical upper limits
  15. GRB 250713A: OHP/T193 upper limit
  16. GRB 250713A: SVOM/C-GFT upper limit
  17. GRB 250706B/C: 7DT Follow-up Observations
  18. GRB 250713A: EP-FXT counterpart detection
  19. EP250711a: COLIBRÍ continuous optical observations
  20. GRB 250713A: JinShan optical upper limits
  21. GRB 250713A: SVOM detection of a long burst
  22. GRB 250711A: DDOTI Optical Upper Limit
  23. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  24. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  25. GRB 250711A: SVOM/GRM observation
  26. EP250711a: NOT optical counterpart candidate
  27. EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  28. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  29. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  30. GRB 250704A: GRANDMA observations
  31. GRB 250704A: SVOM/ECLAIRs refined analysis
  32. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  33. GRB 250702B,D,E/EP250702A: JCMT sub-mm observations at 350 GHz
  34. IceCube-250708A: No Candidates from WINTER
  35. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  36. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  37. IPN triangulation of GRB 250704B (short/hard, consistent with EP 250704a)
  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. EP250704a/GRB250704B : HCT optical and NIR upper limits
  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. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  50. GRB 250706B/C: Fermi-LAT detection
  51. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  52. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  53. GRB 250706B: Swift/UVOT Detection
  54. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  55. GRB 250702F: GRANDMA observations
  56. GRB 250706A: Swift/UVOT Upper Limits
  57. GRB 250706B: REM optical observations
  58. GRB 250706A: REM optical/NIR observations
  59. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  60. IceCube-250416A: DDOTI Optical Upper Limit
  61. IceCube-250706A: COLIBRÍ optical upper limits
  62. GRB 250706A: JinShan optical upper limits
  63. GRB 250706A: SAO RAS optical observations
  64. EP250704A: NOWT Detection
  65. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  66. GRB 250706B: iTelescope optical observations
  67. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  68. GRB 250706B: SVOM/VT optical observation
  69. GRB 250706B: TRT bright optical counterpart detection
  70. GRB 250706A: GROWTH-India Telescope optical upper limit
  71. GRB 250706B: SVOM detection of a long burst
  72. GRB 250706A: Swift detection of a burst
  73. GRB 250704B: Swift-XRT refined Analysis
  74. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  75. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart
  76. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  77. GRB 250704B: Swift/UVOT Upper Limits
  78. GRB 250704A: Swift/UVOT Detection
  79. LIGO/Virgo/KAGRA S250705cb: Identification of a GW compact binary merger candidate
  80. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  81. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  82. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  83. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  84. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  85. GRB 250702F: Kilonova-Catcher optical afterglow detection
  86. GRB 250702F: Monte Agliale Observatory optical observations
  87. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  88. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  89. EP250704a / GRB 250704B: JinShan optical observations
  90. EP250704a / GRB 250704B: SAO RAS optical observations
  91. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  92. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  93. EP250704a / GRB 250704B: Pan-STARRS iz-band imaging and photometry
  94. EP 250704a: BOOTES-5 optical detection
  95. EP250704a: refined analysis of the EP-WXT and FXT follow-up observations
  96. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  97. GRB 250704A: Swift-XRT afterglow detection
  98. EP250704a / GRB 250704B - REM observations
  99. GRB 250702F: GROWTH-India Telescope optical observations
  100. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection

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