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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"

27220 results found.

  1. EP250321a: refined analysis of the EP-WXT and EP-FXT observations
  2. EP250321a: KAIT optical observations
  3. EP250321A: COLIBRÍ Continuing Optical Observations
  4. GRB 250225B: GECAM-A detection
  5. GRB 250312A: GECAM-A detection
  6. GRB 250321C: Fermi GBM Final Real-time Localization
  7. GRB 250320B: Fermi GBM Observation
  8. GRB 250321A: Swift-BAT refined analysis
  9. GRB 250321A: Swift-XRT refined Analysis
  10. GRB 250320B: Fermi-LAT detection
  11. GRB 250321B: SVOM detection of a sub-threshold transient event
  12. EP250321a: SVOM/VT optical observation
  13. EP 250321A: Optical counterpart detection by LCO.
  14. EP250321a: Kinder optical follow-up observations
  15. GRB 250321A: Swift/UVOT Upper Limits
  16. GRB 250320B: SVOM/GRM observation of a long burst
  17. EP250321a: LCO optical counterpart detection
  18. EP250321a: Swift-XRT detection of an X-ray source
  19. EP250321A: COLIBRÍ Optical Observations
  20. EP250321a: VLT/X-shooter redshift z = 4.368
  21. EP250321a: REM optical/NIR afterglow detection
  22. Fermi GRB 250320B: Global MASTER-Net observations report
  23. EP250321a: TRT optical counterpart detection
  24. EP250321a: Global MASTER-Net observations report
  25. Swift GRB 250321A: Global MASTER-Net observations report
  26. Fermi GRB 250321A: Global MASTER-Net observations report
  27. EP250321a: Einstein Probe detection of an X-ray transient
  28. GRB 250321A: GOTO optical upper limits
  29. GRB 250321A: Swift-XRT localisation
  30. EP250226a/GRB 250226A: KAIT optical observations
  31. GRB 250321A: Fermi GBM Observation
  32. GRB 250321A: Swift detection of a burst
  33. GRB 250321A: Fermi GBM Final Real-time Localization
  34. GRB 250320B: Fermi GBM Final Real-time Localization
  35. GRB 250309B: Proof-of-concept for Joint ZTF+EP Experiment
  36. GRB 250317B: Mondy AZT-33IK Continued Optical Observations
  37. GRB 250320A: Fermi GBM Final Real-time Localization
  38. Fermi GRB 250319B: Global MASTER-Net observations report
  39. GRB 250319B: Fermi GBM Final Localization
  40. GRB 250319A: Fermi GBM Final Localization
  41. GRB 250317D: EIRSAT-1 GMOD Detection
  42. EP250302a: VLA observations
  43. GRB 250317B: OHP/T193 continued follow-up
  44. GRB 250317C: SVOM/GRM observation of a long burst
  45. GRB 250317B: Leavitt Observatory optical upper limit
  46. GRB 250317B: Mondy AZT-33IK Optical Observations
  47. GRB 250317B: NOT optical observations suggest an optical plateau phase
  48. GRB 250317C: GECAM-B detection
  49. GRB 250317B: OHP/T193 optical observations
  50. Fermi trigger No 763933627: Global MASTER-Net observations report
  51. GRB250312A: Swift/UVOT Upper Limits
  52. GRB 250317B: REM optical/NIR observations
  53. GRB 250316A: Swift/UVOT Upper Limits
  54. GRB 250314A: REM optical/NIR upper limits
  55. GRB 250316A: AbAO AS-32 Optical Upper Limit
  56. EP 250317B: Fading optical counterpart detection by LCO
  57. GRB 250317B: LCO detection of the fading optical afterglow
  58. GRB 250317B: refined SVOM/MXT analysis
  59. GRB 250317B: SVOM/VT detection of an optical candidate from VHF data
  60. GRB 250317B: SVOM/F-GFT (COLIBRÍ) Detection of a Fading Optical Counterpart
  61. GRB 250317B: SVOM detection of a burst / correction to GRB name of GCN 39752
  62. GRB 250317B: SVOM detection of a burst
  63. GRB 250316A: Fermi GBM Observation
  64. Fermi trigger No 763862734: Global MASTER-Net observations report
  65. GRB 250317A: Fermi GBM Final Real-time Localization
  66. Fermi GRB 250316A: Global MASTER-Net observations report
  67. GRB 250314A: SVOM/GRM analysis
  68. GRB 250316A: Swift/BAT-GUANO arcminute localization of a burst
  69. The EP-WXT trigger 01709132801 is likely a flaring star
  70. GRB 250316A: Fermi GBM Final Real-time Localization
  71. GRB 250315A/EP250315A: Fermi-GBM Sub-Threshold Detection
  72. GRB 250314A: EP-FXT afterglow detection
  73. EP250315a: refined analysis of the EP-WXT and EP-FXT observations
  74. GRB 250313.89 / Fermi trigger 763594063: bright OT AT 2025ehi detection
  75. EP250315a: optical counterpart candidate detected by Gemini North
  76. EP250315a: Einstein Probe detection of an X-ray transient
  77. GRB 250226A: Mondy AZT-33IK and Koshka Zeiss-1000 Optical Upper Limits
  78. SVOM/MXT upper limit on GRB 250314A
  79. GRB 250314A: SVOM/VT upper limit
  80. GRB 250314A: NOT near-infrared candidate counterpart
  81. GRB 250313A: Fermi GBM Detection
  82. GRB 250313A: CALET Gamma-Ray Burst Monitor detection
  83. GRB 250312B: Fermi GBM Observation
  84. GRB250314A: SVOM/VT lack of bright optical candidate from VHF data
  85. GRB 250314A: SVOM detection of a burst
  86. GRB 250313B: SVOM/GRM observation of a soft bright short burst
  87. GRB 250313A: SVOM/GRM observation of a bright long burst
  88. IceCube-250309A: MASTER detection of J140105.33-091631.6 blazar flare with Zhirkov effect
  89. Fermi trigger No 763581136: Global MASTER-Net observations report
  90. GRB 250313A: Fermi-LAT detection
  91. GRB 250312B: Swift/BAT-GUANO localization skymap of a burst
  92. EP trigger ID 01709061302: Lick/Kast spectroscopy with the 3 m Shane telescope
  93. Fermi GRB 250313A: Global MASTER-Net observations report
  94. GRB 250309B: PRIME near-infrared upper limits in 2nd epoch
  95. GRB 250313A???: BALROG localization (Fermi Trigger / GRB 250313607)
  96. GRB 250313A: Fermi GBM Final Real-time Localization
  97. The EP-WXT trigger 01709132551 is not a real source
  98. EP250304a: SVOM/VT optical observation
  99. EP250311a/GRB 250311A: EP-FXT follow-up observation
  100. EP250302a: Chandra X-ray Detection

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