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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').
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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"

18510 results found.

  1. GRB 250505B: SVOM/GRM observation of a short burst
  2. GRB 250502A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  3. EP250508a: REM optical/NIR observations
  4. GRB 250506A: Swift-XRT afterglow detection
  5. EP250508a: COLIBRÍ Optical Limit
  6. EP250508a: Einstein Probe detection of an X-ray transient
  7. GRB 250506A: Swift/UVOT Upper Limits
  8. GRB 250507A: follow-up observation with EP-FXT
  9. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  10. GRB 250507A: REM optical/NIR observations
  11. GRB 250507A: SVOM/VT optical upper limit
  12. GRB 250507A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  13. EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032
  14. GRB 250507A: SVOM detection of a long burst
  15. GRB 250506A: Mephisto optical upper limits
  16. GRB 250502A: Bassano Bresciano Observatory upper limit
  17. GRB 250506A: Xinglong 2.16m optical upper limit
  18. SVOM/sb25050601: EP-FXT observations
  19. GRB 250506A: REM optical/NIR upper limits
  20. GRB 250506A: TRT optical observations
  21. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) Upper Limits on the Optical Counterpart
  22. GRB 250504A: VLT/X-shooter upper limits
  23. GRB 250504A: REM optical/NIR observations
  24. GRB 250502A: REM optical/NIR observations
  25. GRB 250504A: MeerLICHT optical afterglow detection
  26. GRB 250504A: Enhanced Swift-XRT position
  27. GRB 250504A: Swift detection of a burst
  28. Swift GRB250504.98: Global MASTER-Net observations report
  29. GRB 250502A: Swift/UVOT Follow up
  30. GRB 250502A: KAIT optical observations
  31. GRB 250502A: Montarrenti Observatory optical detection
  32. GRB 250502A: Swift-XRT afterglow detection
  33. GRB 250502A: NOT optical observations
  34. GRB 250502B: AstroSat CZTI detection
  35. GRB 250502A: AKO Optical Afterglow Detection
  36. GRB 250502A: LCO optical counterpart detection
  37. GRB 250502A: Redshift from OSIRIS+/GTC z = 2.163
  38. GRB 250407A: VZLUSAT-2 detection
  39. GRB 250502B: DDOTI Optical Observations
  40. GRB 250502A: Early optical counterpart detection by LCO.
  41. GRB 250430A: Swift/UVOT Detection
  42. GRB 250502A: TRT optical afterglow confirmation
  43. GRB 250430A: Enhanced Swift-XRT position
  44. GRB 250502A: SVOM/COLIBRÍ (FM-GFT) Detection of a Bright Optical Counterpart Candidate
  45. GRB 250502A: SVOM detection of a burst
  46. GRB 250430A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  47. GRB 250430A: KAIT optical observations
  48. GRB 250430A / EP250430a: J-band upper limits with WINTER
  49. GRB 250430A: DDOTI Optical Observations
  50. GRB 250430A: Leavitt Observatory optical upper limit
  51. GRB 250430A: Bassano Bresciano Observatory upper limit
  52. GRB 250430A : MITSuME Akeno optical upper limits
  53. SVOM/sb25043004: EP-FXT observations
  54. EP250430a/GRB 250430A: Einstein Probe WXT detection of the X-ray prompt emission
  55. GRB 250430A: AKO Optical Afterglow Detection
  56. GRB 250430A: Kanata optical upper limit
  57. EP 250427A: Optical counterpart detection by LCO.
  58. GRB 250430A: Swift detection of a burst with optical counterpart
  59. EP250427a/GRB250427A: HCT optical follow-up
  60. SVOM/sb25043004: SVOM detection of a X-ray transient
  61. EP250428b: refined analysis of the EP-FXT follow-up observation
  62. EP250428b: GROWTH-India telescope optical upper limit
  63. EP250428b: SAO RAS optical upper limit
  64. EP250428b: LAST optical upper limit
  65. GRB 250427A: Swift/UVOT Detection
  66. EP250428b: Einstein Probe detection of a fast X-ray transient
  67. EP250427a: EP-FXT follow-up observations
  68. EP250427A: COLIBRÍ Continuing Optical Observations
  69. GRB250427A/EP250427a GIT optical afterglow detection:
  70. EP250427a: LT optical counterpart detection
  71. EP250427a / GRB 250427A: LCO optical counterpart detection
  72. EP250427a: REM optical/NIR afterglow detection
  73. GRB 250424A: LCO optical observation
  74. EP250427A: COLIBRÍ Optical Detection
  75. EP250427a: TRT optical counterpart detection
  76. EP250427a: Einstein Probe detection of a fast X-ray transient
  77. GRB 250424A: SVOM/GRM observation of a long burst
  78. GRB 250424A: PRIME near-infrared detection
  79. GRB 250424A: WINTER J-band detection
  80. GRB 250419A: Mondy Optical Observations
  81. GRB 250424A: Swift/UVOT Detection
  82. GRB 250424A: Skynet Optical Observations
  83. GRB 250424A: Kilonova-Catcher optical afterglow detection
  84. GRB 250424A: Enhanced Swift-XRT position
  85. GRB 250424A: COLIBRÍ Detection of a Bright Optical Counterpart
  86. GRB 250424A: BlackGEM optical afterglow detection
  87. GRB 250424A: DDOTI Afterglow Detection
  88. GRB 250424A: REM optical/NIR afterglow detection
  89. GRB 250424A: Swift detection of a burst with an optical counterpart
  90. LIGO/Virgo/KAGRA S250328ae: Subaru/PFS Spectroscopic Follow up and Candidates
  91. EP250421a: Nickel optical upper limit
  92. IceCube-250421A: DDOTI Detection of the LAST Candidate
  93. GRB 250419A: Mephisto Multi-band Optical Detection
  94. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  95. IC-250421A: LAST optical observations of the IceCube neutrino candidate
  96. EP250421a: NOT optical observations
  97. GRB 250419A: Optical Observations via Virtual Telescope Project
  98. EP250421a: REM optical upper limit
  99. EP250421A: COLIBRÍ Optical Upper Limit
  100. GRB 250419A: Mondy Continued Optical Observations

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