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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

25035 results found.

  1. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  2. GRB 250716A: Fermi GBM Observation
  3. GRB 250714A: SVOM/GRM observation
  4. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  5. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  6. GRB 250713A: Mephisto optical upper limits
  7. GRB 250713A: SVOM/VT optical upper limit
  8. GRB 250713A: NOT optical upper limits
  9. GRB 250713A: OHP/T193 upper limit
  10. GRB 250713A: SVOM/C-GFT upper limit
  11. GRB 250706B/C: 7DT Follow-up Observations
  12. GRB 250713A: Swift-XRT observations
  13. GRB 250713A: EP-FXT counterpart detection
  14. EP250711a: COLIBRÍ continuous optical observations
  15. GRB 250706A: Swift-BAT refined analysis
  16. GRB 250702F: Swift-BAT refined analysis
  17. GRB 250628A: Swift-BAT refined analysis
  18. LIGO/Virgo/KAGRA S250712cd: Updated Sky localization
  19. GRB 250713A: JinShan optical upper limits
  20. GRB 250713A: SVOM detection of a long burst
  21. EP250711a: Global MASTER-Net observations report
  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. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  28. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  29. GRB 250704A: GRANDMA observations
  30. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  31. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  32. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  33. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  34. IceCube-250708A: No Candidates from WINTER
  35. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  36. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  37. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  38. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  39. EP-WXT trigger 01709181970. confirmation of a stellar flare by BOOTES-6
  40. EP250704a/GRB 250704B: 10 GHz VLA detection
  41. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 4-Update Localization Volume
  42. IceCube-250706A: No Candidates from WINTER
  43. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  44. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  45. LIGO/Virgo/KAGRA S250705cb: Updated Sky localization
  46. LIGO/Virgo/KAGRA S250704ab: Updated Sky localization and EM Bright Classification
  47. LIGO/Virgo/KAGRA S250702n: Updated Sky localization
  48. LIGO/Virgo/KAGRA S250701bq: Updated Sky localization
  49. EP250704a/GRB250704B : HCT optical and NIR upper limits
  50. LIGO/Virgo/KAGRA S250701bp: Updated Sky localization
  51. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  52. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  53. GRB 250702F: radio detection with the VLA
  54. IceCube-250706A: EP-FXT follow-up observations
  55. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  56. GRB 250706B/C: Fermi-LAT detection
  57. IceCube-250706A: Global MASTER-Net observations report
  58. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  59. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  60. GRB 250706B: Swift/UVOT Detection
  61. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  62. GRB 250702F: GRANDMA observations
  63. GRB 250706A: Swift-XRT refined Analysis
  64. GRB 250706B: refined SVOM/MXT data analysis
  65. GRB 250706A: Swift/UVOT Upper Limits
  66. GRB 250706B: REM optical observations
  67. GRB 250706A: REM optical/NIR observations
  68. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  69. IceCube-250416A: DDOTI Optical Upper Limit
  70. IceCube-250706A: COLIBRÍ optical upper limits
  71. GRB 250706A: JinShan optical upper limits
  72. GRB 250706A: SAO RAS optical observations
  73. EP250704A: NOWT Detection
  74. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  75. GRB250706B: Swift-XRT counterpart detection
  76. GRB 250706B: iTelescope optical observations
  77. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  78. GRB 250706B: SVOM/VT optical observation
  79. GRB 250706B: TRT bright optical counterpart detection
  80. GRB 250706A: GROWTH-India Telescope optical upper limit
  81. GRB 250706B: SVOM detection of a long burst
  82. GRB 250706A: Swift detection of a burst
  83. GRB 250704B: Swift-XRT refined Analysis
  84. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  85. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart
  86. GRB 250703A: EIRSAT-1 GMOD Detection
  87. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  88. GRB 250704B: Swift/UVOT Upper Limits
  89. GRB 250704A: Swift/UVOT Detection
  90. LIGO/Virgo/KAGRA S250705cb: Identification of a GW compact binary merger candidate
  91. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  92. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  93. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  94. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  95. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  96. GRB 250702F: Kilonova-Catcher optical afterglow detection
  97. GRB 250702F: Monte Agliale Observatory optical observations
  98. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  99. EP250704a / GRB 250704B: JinShan optical observations
  100. EP250704a / GRB 250704B: SAO RAS optical observations

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