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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"

43940 results found.

  1. GRB 250321A: Swift-BAT refined analysis
  2. GRB 250321A: Swift-XRT refined Analysis
  3. GRB 250320B: Fermi-LAT detection
  4. GRB 250321B: SVOM detection of a sub-threshold transient event
  5. EP250321a: SVOM/VT optical observation
  6. EP 250321A: Optical counterpart detection by LCO.
  7. EP250321a: Kinder optical follow-up observations
  8. GRB 250320B: SVOM/GRM observation of a long burst
  9. EP250321a: LCO optical counterpart detection
  10. EP250321a: Swift-XRT detection of an X-ray source
  11. EP250321A: COLIBRÍ Optical Observations
  12. EP250321a: VLT/X-shooter redshift z = 4.368
  13. GRB 250320B: AstroSat CZTI detection
  14. EP250321a: REM optical/NIR afterglow detection
  15. Fermi GRB 250320B: Global MASTER-Net observations report
  16. EP250321a: BOOTES-5/JGT optical afterglow detection
  17. EP250321a: TRT optical counterpart detection
  18. EP250321a: Global MASTER-Net observations report
  19. Swift GRB 250321A: Global MASTER-Net observations report
  20. Fermi GRB 250321A: Global MASTER-Net observations report
  21. EP250321a: Einstein Probe detection of an X-ray transient
  22. GRB 250321A: GOTO optical upper limits
  23. GRB 250321A: Swift-XRT localisation
  24. EP250226a/GRB 250226A: KAIT optical observations
  25. GRB 250321A: Fermi GBM Observation
  26. GRB 250321A: Swift detection of a burst
  27. GRB 250321A: Fermi GBM Final Real-time Localization
  28. GRB 250320B: Fermi GBM Final Real-time Localization
  29. GRB 250309B: Proof-of-concept for Joint ZTF+EP Experiment
  30. GRB 250317B: Mondy AZT-33IK Continued Optical Observations
  31. GRB 250320A: Fermi GBM Final Real-time Localization
  32. Fermi GRB 250319B: Global MASTER-Net observations report
  33. FRB 20250316A: Upper limits for gamma-ray transient from Insight-HXMT/HE observations
  34. GRB 250313A: GRBAlpha detection
  35. LIGO/Virgo/KAGRA S250206dm: LIGHETR followup observations of AT2025azn
  36. GRB 250317B: SVOM/COLIBRI (F-GFT) follow-up observations
  37. GRB 250319B: Fermi GBM Final Localization
  38. GRB 250319A: Fermi GBM Final Localization
  39. GRB 250317D: EIRSAT-1 GMOD Detection
  40. LIGO/Virgo/KAGRA S250319bu: Updated Sky localization
  41. GRB 250314A: ATCA radio upper limits
  42. EP250302a: VLA observations
  43. GRB 250317B: OHP/T193 continued follow-up
  44. LIGO/Virgo/KAGRA S250319bu: Identification of a GW compact binary merger candidate
  45. GRB 250317C: SVOM/GRM observation of a long burst
  46. GRB 250317B: Leavitt Observatory optical upper limit
  47. GRB 250309B/AT2025dws: further ATCA observations
  48. GRB 250317B: Mondy AZT-33IK Optical Observations
  49. GRB 250317C: AstroSat CZTI detection
  50. GRB 250317B: NOT optical observations suggest an optical plateau phase
  51. GRB 250317B: GTC/OSIRIS+ spectroscopic redshift z=3.44
  52. GRB 250317C: GECAM-B detection
  53. GRB 250317B: OHP/T193 optical observations
  54. Fermi trigger No 763933627: Global MASTER-Net observations report
  55. GRB250312A: Swift/UVOT Upper Limits
  56. GRB 250317B: REM optical/NIR observations
  57. GRB 250317B: Swift-XRT observations
  58. GRB 250316A: Swift/UVOT Upper Limits
  59. GRB 250314A: REM optical/NIR upper limits
  60. GRB 250316A: AbAO AS-32 Optical Upper Limit
  61. EP 250317B: Fading optical counterpart detection by LCO
  62. GRB 250316A: Swift-XRT afterglow detection
  63. GRB 250317B: LCO detection of the fading optical afterglow
  64. GRB 250317B: refined SVOM/MXT analysis
  65. GRB 250317B: SVOM/VT detection of an optical candidate from VHF data
  66. GRB 250317B: SVOM/F-GFT (COLIBRÍ) Detection of a Fading Optical Counterpart
  67. GRB 250317B: SVOM detection of a burst / correction to GRB name of GCN 39752
  68. GRB 250317B: SVOM detection of a burst
  69. GRB 250316A: Fermi GBM Observation
  70. GRB 250316A: Swift-XRT observations
  71. Fermi trigger No 763862734: Global MASTER-Net observations report
  72. GRB 250317A: Fermi GBM Final Real-time Localization
  73. Fermi GRB 250316A: Global MASTER-Net observations report
  74. GRB 250314A: SVOM/GRM analysis
  75. GRB 250316A: Swift ToO observations
  76. GRB 250316A: Swift/BAT-GUANO arcminute localization of a burst
  77. GRB 250314A: GTC z-band upper limit and updated photo-z ~ 7.27
  78. The EP-WXT trigger 01709132801 is likely a flaring star
  79. GRB 250316A: Fermi GBM Final Real-time Localization
  80. GRB 250315A/EP250315A: Fermi-GBM Sub-Threshold Detection
  81. GRB 250314A: EP-FXT afterglow detection
  82. EP250315a: refined analysis of the EP-WXT and EP-FXT observations
  83. GRB 250314A: Swift/UVOT Upper Limits
  84. GRB 250312B: GRBAlpha detection
  85. GRB 250313.89 / Fermi trigger 763594063: bright OT AT 2025ehi detection
  86. GRB 250314A: Swift XRT Detection
  87. EP250315a: optical counterpart candidate detected by Gemini North
  88. GRB 250314A: VLT/X-shooter dropout, redshift z ~ 7.3
  89. EP250315a: Einstein Probe detection of an X-ray transient
  90. GRB 250226A: Mondy AZT-33IK and Koshka Zeiss-1000 Optical Upper Limits
  91. SVOM/MXT upper limit on GRB 250314A
  92. GRB 250314A: SVOM/VT upper limit
  93. GRB 250314A: NOT near-infrared candidate counterpart
  94. GRB 250313A: Fermi GBM Detection
  95. GRB 250313A: CALET Gamma-Ray Burst Monitor detection
  96. GRB 250312B: Fermi GBM Observation
  97. GRB 250313A: Swift-XRT observations
  98. GRB250314A: SVOM/VT lack of bright optical candidate from VHF data
  99. Konus-Wind detection of GRB 250313A
  100. Konus-Wind detection of GRB 250308A

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