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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

28115 results found.

  1. GRB 250713A: JinShan optical upper limits
  2. GRB 250713A: SVOM detection of a long burst
  3. EP250711a: Global MASTER-Net observations report
  4. GRB 250711A: DDOTI Optical Upper Limit
  5. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  6. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  7. GRB 250711A: SVOM/GRM observation
  8. EP250711a: NOT optical counterpart candidate
  9. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  10. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  11. GRB 250704A: GRANDMA observations
  12. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  13. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  14. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  15. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  16. IceCube-250708A: No Candidates from WINTER
  17. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  18. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  19. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  20. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  21. EP-WXT trigger 01709181970. confirmation of a stellar flare by BOOTES-6
  22. EP250704a/GRB 250704B: 10 GHz VLA detection
  23. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 4-Update Localization Volume
  24. IceCube-250706A: No Candidates from WINTER
  25. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  26. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  27. LIGO/Virgo/KAGRA S250705cb: Updated Sky localization
  28. LIGO/Virgo/KAGRA S250704ab: Updated Sky localization and EM Bright Classification
  29. LIGO/Virgo/KAGRA S250702n: Updated Sky localization
  30. LIGO/Virgo/KAGRA S250701bq: Updated Sky localization
  31. EP250704a/GRB250704B : HCT optical and NIR upper limits
  32. LIGO/Virgo/KAGRA S250701bp: Updated Sky localization
  33. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  34. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  35. GRB 250702F: radio detection with the VLA
  36. IceCube-250706A: EP-FXT follow-up observations
  37. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  38. GRB 250706B/C: Fermi-LAT detection
  39. IceCube-250706A: Global MASTER-Net observations report
  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-XRT refined Analysis
  46. GRB 250706B: refined SVOM/MXT data analysis
  47. GRB 250706A: Swift/UVOT Upper Limits
  48. GRB 250706B: REM optical observations
  49. GRB 250706A: REM optical/NIR observations
  50. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  51. IceCube-250416A: DDOTI Optical Upper Limit
  52. IceCube-250706A: COLIBRÍ optical upper limits
  53. GRB 250706A: JinShan optical upper limits
  54. GRB 250706A: SAO RAS optical observations
  55. EP250704A: NOWT Detection
  56. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  57. GRB250706B: Swift-XRT counterpart detection
  58. GRB 250706B: iTelescope optical observations
  59. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  60. GRB 250706B: SVOM/VT optical observation
  61. GRB 250706B: TRT bright optical counterpart detection
  62. GRB 250706A: GROWTH-India Telescope optical upper limit
  63. GRB 250706B: SVOM detection of a long burst
  64. GRB 250706A: Swift detection of a burst
  65. GRB 250704B: Swift-XRT refined Analysis
  66. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  67. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart
  68. GRB 250703A: EIRSAT-1 GMOD Detection
  69. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  70. GRB 250704B: Swift/UVOT Upper Limits
  71. GRB 250704A: Swift/UVOT Detection
  72. LIGO/Virgo/KAGRA S250705cb: Identification of a GW compact binary merger candidate
  73. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  74. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  75. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  76. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  77. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  78. GRB 250702F: Kilonova-Catcher optical afterglow detection
  79. GRB 250702F: Monte Agliale Observatory optical observations
  80. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  81. EP250704a / GRB 250704B: JinShan optical observations
  82. EP250704a / GRB 250704B: SAO RAS optical observations
  83. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  84. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 3-Initial Localization Volume
  85. EP250704a: refined analysis of the EP-WXT and FXT follow-up observations
  86. LIGO/Virgo/KAGRA S250704ab: Upper limits from Fermi-GBM Observations
  87. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  88. EP250704a / GRB250704B: Swift-XRT counterpart detection
  89. GRB 250704A: Swift-XRT afterglow detection
  90. EP250704a / GRB 250704B - REM observations
  91. GRB 250702F: GROWTH-India Telescope optical observations
  92. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection
  93. GRB 250704A: REM retraction of optical afterglow detection and updated limit
  94. EP250702a: WFST optical observations
  95. EP250704a: COLIBRÍ optical counterpart candidate
  96. EP250704a: Einstein Probe detection of an X-ray transient
  97. GRB 250704A: REM detection of the optical afterglow
  98. LIGO/Virgo/KAGRA S250704ab: Coverage and upper limits from MAXI/GSC observations
  99. LIGO/Virgo/KAGRA S250704ab: Identification of a GW compact binary merger candidate
  100. GRB 250704A: SVOM detection of a burst

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