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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"

20521 results found.

  1. GRB 250424A: COLIBRÍ detection of the associated supernova
  2. GRB 250502A: TESS observations
  3. EP250512a/GRB 250512B: REM optical/NIR observations
  4. EP250511a: Koshka Zeiss-1000 Optical Upper Limit
  5. EP250511a: Gemini optical counterpart observation
  6. EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
  7. EP250511a: Mephisto optical upper limits
  8. GRB 250512B: SVOM detection of a burst
  9. EP250512a: Einstein Probe detection of an X-ray transient
  10. EP250511a: REM optical/NIR observations
  11. EP250511a: Einstein Probe follow-up obsevation and refined analysis
  12. EP250511a: COLIBRÍ optical counterpart candidate
  13. EP250511a: Einstein Probe detection of an X-ray transient
  14. EP250508a: Gemini NIR upper limits
  15. GRB 250510A: Swift-XRT observations
  16. IceCube-250506A: No Transient Candidates from the Zwicky Transient Facility
  17. GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
  18. GRB 250510A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  19. GRB 250507A: J-band observations with WINTER
  20. GRB 250509A: Enhanced Swift-XRT position
  21. GRB 250509A: Swift detection of a burst
  22. GRB 250506A: NOT optical upper limits
  23. EP250508a: Liverpool Telescope optical upper limits
  24. EP250508a: KAIT optical upper limit
  25. GRB 250507A: KAIT optical upper limit
  26. EP250508a: refined analysis of the EP-WXT and EP-FXT observations
  27. GRB 250505B: SVOM/GRM observation of a short burst
  28. GRB 250502A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  29. EP250508a: REM optical/NIR observations
  30. GRB 250506A: Swift-XRT afterglow detection
  31. EP250508a: COLIBRÍ Optical Limit
  32. EP250508a: Einstein Probe detection of an X-ray transient
  33. IceCube-250506A: Upper limits from a search for additional neutrino events in IceCube
  34. GRB 250506A: Swift/UVOT Upper Limits
  35. GRB 250427B : SVOM detection of a burst through offline search
  36. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  37. GRB 250507A: REM optical/NIR observations
  38. GRB 250507A: SVOM/VT optical upper limit
  39. GRB 250507A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  40. EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032
  41. GRB 250507A: SVOM detection of a long burst
  42. GRB 250506A: Mephisto optical upper limits
  43. GRB 250502A: Bassano Bresciano Observatory upper limit
  44. GRB 250506A: Xinglong 2.16m optical upper limit
  45. GRB 250506A: REM optical/NIR upper limits
  46. GRB 250506A: TRT optical observations
  47. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) Upper Limits on the Optical Counterpart
  48. GRB 250504A: VLT/X-shooter upper limits
  49. GRB 250504A: REM optical/NIR observations
  50. GRB 250502A: REM optical/NIR observations
  51. GRB 250504A: MeerLICHT optical afterglow detection
  52. GRB 250504A: Enhanced Swift-XRT position
  53. GRB 250504A: Swift detection of a burst
  54. GRB 250504A: Fermi GBM Final Real-time Localization
  55. GRB 250502A: Swift/UVOT Follow up
  56. GRB 250502A: KAIT optical observations
  57. GRB 250502A: Montarrenti Observatory optical detection
  58. GRB 250502A: Swift-XRT afterglow detection
  59. GRB 250502A: NOT optical observations
  60. GRB 250502B: AstroSat CZTI detection
  61. GRB 250502A: AKO Optical Afterglow Detection
  62. GRB 250502A: LCO optical counterpart detection
  63. GRB 250502A: Redshift from OSIRIS+/GTC z = 2.163
  64. GRB 250502B: DDOTI Optical Observations
  65. GRB 250502A: Early optical counterpart detection by LCO.
  66. GRB 250430A: Swift/UVOT Detection
  67. GRB 250502A: TRT optical afterglow confirmation
  68. GRB 250430A: Enhanced Swift-XRT position
  69. GRB 250502A: SVOM/COLIBRÍ (FM-GFT) Detection of a Bright Optical Counterpart Candidate
  70. GRB 250502A: SVOM detection of a burst
  71. GRB 250430A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  72. GRB 250430A: KAIT optical observations
  73. GRB 250430A / EP250430a: J-band upper limits with WINTER
  74. GRB 250430A: NUTTelA-TAO Early Measurements
  75. GRB 250430A: DDOTI Optical Observations
  76. GRB 250430A: Leavitt Observatory optical upper limit
  77. GRB 250430A: Bassano Bresciano Observatory upper limit
  78. GRB 250430A : MITSuME Akeno optical upper limits
  79. GRB 250430A / EP250430a: VLT/X-shooter spectroscopic redshift z = 0.767
  80. EP250430a/GRB 250430A: Einstein Probe WXT detection of the X-ray prompt emission
  81. IceCube-250429A: Upper limits from a search for additional neutrino events in IceCube
  82. IceCube-250426A: Upper limits from a search for additional neutrino events in IceCube
  83. GRB 250430A: AKO Optical Afterglow Detection
  84. GRB 250430A: Kanata optical upper limit
  85. EP 250427A: Optical counterpart detection by LCO.
  86. GRB 250430A: Swift detection of a burst with optical counterpart
  87. EP250427a/GRB250427A: HCT optical follow-up
  88. SVOM/sb25043004: SVOM detection of a X-ray transient
  89. EP250428b: GROWTH-India telescope optical upper limit
  90. EP250428b: SAO RAS optical upper limit
  91. EP250428b: LAST optical upper limit
  92. GRB 250427A: Swift/UVOT Detection
  93. EP250428b: Einstein Probe detection of a fast X-ray transient
  94. EP250427A: COLIBRÍ Continuing Optical Observations
  95. GRB250427A/EP250427a GIT optical afterglow detection:
  96. EP250427a: LT optical counterpart detection
  97. EP250427a / GRB 250427A: LCO optical counterpart detection
  98. EP250427a: REM optical/NIR afterglow detection
  99. GRB 250424A: LCO optical observation
  100. EP250427A: COLIBRÍ Optical Detection

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