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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"

32692 results found.

  1. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  2. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  3. EP250704a / GRB 250704B: JinShan optical observations
  4. GRB 250704A: SVOM/VT optical observation
  5. EP250704a / GRB 250704B: SAO RAS optical observations
  6. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  7. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  8. EP250704a / GRB 250704B: SVOM/VT optical blue counterpart
  9. EP250704a / GRB 250704B: Pan-STARRS iz-band imaging and photometry
  10. EP 250704a: BOOTES-5 optical detection
  11. EP250704a: refined analysis of the EP-WXT and FXT follow-up observations
  12. LIGO/Virgo/KAGRA S250704ab: Upper limits from Fermi-GBM Observations
  13. GRB 250702A: Insight-HXMT detection
  14. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  15. GRBs 250702B/C/D/E / EP250702a: Swift/UVOT Upper Limits
  16. EP250704a / GRB250704B: Swift-XRT counterpart detection
  17. GRB 250704A: Swift-XRT afterglow detection
  18. GRB 250702B / EP2050702a: FTW optical and NIR observations
  19. Konus-Wind detection of GRB 250702F
  20. EP250704a / GRB 250704B - REM observations
  21. GRB 250702F: GROWTH-India Telescope optical observations
  22. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection
  23. GRB 250704A: REM retraction of optical afterglow detection and updated limit
  24. EP250702a: WFST optical observations
  25. EP250704a: COLIBRÍ optical counterpart candidate
  26. EP250704a: Einstein Probe detection of an X-ray transient
  27. GRB 250702F: optical photometry from Konkoly
  28. GRB 250704A: REM detection of the optical afterglow
  29. LIGO/Virgo/KAGRA S250704ab: Coverage and upper limits from MAXI/GSC observations
  30. GRB 250702F: SVOM/VT optical observation
  31. LIGO/Virgo/KAGRA S250704ab: Identification of a GW compact binary merger candidate
  32. GRB 250702F: Swift/UVOT Detection
  33. GRB 250702A: CALET Gamma-Ray Burst Monitor detection
  34. Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
  35. Fermi GRB 250703A: Global MASTER-Net observations report
  36. GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
  37. GRB 250702F: Fermi GBM Observation
  38. GRB 250702F: Leavitt Observatory optical observations
  39. GRB 250702F: AKO Optical Afterglow Detection
  40. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  41. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  42. GRB 250702A: GECAM-B detection
  43. GRB 250702F: Skynet Optical Observations
  44. GRB 250424A: VIRT Optical Upper Limit
  45. GRBs 250702B/C/D/E / EP250702a: Swift XRT localization
  46. GRB 250702B,C,D,E/EP250702a: COLIBRÍ optical upper limit
  47. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  48. GRB 250702F: TRT Optical Observation
  49. GRB 250703A: DDOTI Optical Upper Limit
  50. GRBs 250702B,C,D,E / EP250702a: Konus-Wind detection of a hard X-ray transient activity
  51. GRB 250702F: REM optical afterglow detection
  52. EP250702a: Global MASTER-Net observations report
  53. GRB 250702F: DDOTI Optical Observation
  54. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  55. GRB 250702F: COLIBRÍ Observations of the Afterglow
  56. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  57. Fermi GRB 250702E: Global MASTER-Net observations report
  58. Fermi GRB 250702B: Global MASTER-Net observations report
  59. GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient
  60. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  61. GRB 250702F: NOT observations of the optical afterglow
  62. GRB 250702F: MASTER optical afterglow observation
  63. Fermi GRB 250702F: Global MASTER-Net observations report
  64. Fermi GRB 250702C: Global MASTER-Net observations report
  65. GRB 250702F: GOTO optical counterpart detection
  66. GRB 250702F: Swift detection of a burst with an optical counterpart
  67. Fermi GBM Triggers 250702B, C, D and E are likely from the same source
  68. Konus-Wind detection of GRB 250627A
  69. IPN triangulation of GRB 250627A (short)
  70. GRB 250702A: Fermi GBM Detection
  71. LIGO/Virgo/KAGRA S250702n: Identification of a GW compact binary merger candidate
  72. LIGO/Virgo/KAGRA S250701bq: Identification of a GW compact binary merger candidate
  73. LIGO/Virgo/KAGRA S250701bp: Identification of a GW compact binary merger candidate
  74. GRB 250628B: Swift-XRT observations
  75. GRB 250628B: SVOM/VT optical upper limit
  76. GRB 250628B: EP-FXT counterpart detection
  77. LIGO/Virgo/KAGRA S250629bs: Updated Sky localization
  78. GRB 250627A: Insight-HXMT detection
  79. LIGO/Virgo/KAGRA S250629ae: Updated Sky localization
  80. LIGO/Virgo/KAGRA S250629bs: Identification of a GW compact binary merger candidate
  81. LIGO/Virgo/KAGRA S250628am: Identification of a GW compact binary merger candidate (duplicate submission)
  82. LIGO/Virgo/KAGRA S250629ae: Identification of a GW compact binary merger candidate
  83. LIGO/Virgo/KAGRA S250628am: Updated Sky localization
  84. GRB 250628A: REM optical/NIR upper limits
  85. LIGO/Virgo/KAGRA S250628am: Identification of a GW compact binary merger candidate
  86. GRB 250625A: VLT/X-shooter spectroscopic observations at the afterglow position
  87. GRB 250628A: VLT/X-shooter upper limits
  88. GRB 250628A: Swift/UVOT Upper Limits
  89. Fermi GRB 250626A: Global MASTER-Net observations report
  90. Swift GRB 250628A: Global MASTER-Net observations report
  91. GRB 250625A: Swift-BAT refined analysis
  92. GRB 250625A: Leavitt Observatory afterglow detection
  93. GRB 250625A: AbAO and INASAN Kislovodsk Optical Observations
  94. GRB 250625A: GTC/OSIRIS+ spectroscopic observations of the potential host galaxy
  95. GRB 250625A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  96. GRB 250625A: SVOM/C-GFT upper limit in early phase
  97. GRB 250625A: GECAM-B detection
  98. GRB 250625A: Swift/UVOT Upper Limits
  99. GRB 250625A: ABObservatory afterglow detection
  100. GRB 250625A: OHP/T193 optical detection

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