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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"

45778 results found.

  1. EP250321a: Einstein Probe detection of an X-ray transient
  2. GRB 250321A: GOTO optical upper limits
  3. GRB 250321A: Swift-XRT localisation
  4. GRB 250314A: Keck/NIRC2 J-band upper limit
  5. EP250226a/GRB 250226A: KAIT optical observations
  6. GRB 250321A: Fermi GBM Observation
  7. GRB 250321A: Swift detection of a burst
  8. GRB 250321A: Fermi GBM Final Real-time Localization
  9. GRB 250320B: Fermi GBM Final Real-time Localization
  10. GRB 250309B: Proof-of-concept for Joint ZTF+EP Experiment
  11. GRB 250317B: Mondy AZT-33IK Continued Optical Observations
  12. GRB 250320A: Fermi GBM Final Real-time Localization
  13. Fermi GRB 250319B: Global MASTER-Net observations report
  14. FRB 20250316A: Upper limits for gamma-ray transient from Insight-HXMT/HE observations
  15. GRB 250313A: GRBAlpha detection
  16. LIGO/Virgo/KAGRA S250206dm: LIGHETR followup observations of AT2025azn
  17. GRB 250317B: SVOM/COLIBRI (F-GFT) follow-up observations
  18. GRB 250319B: Fermi GBM Final Localization
  19. GRB 250319A: Fermi GBM Final Localization
  20. GRB 250317D: EIRSAT-1 GMOD Detection
  21. LIGO/Virgo/KAGRA S250319bu: Updated Sky localization
  22. GRB 250314A: ATCA radio upper limits
  23. EP250302a: VLA observations
  24. GRB 250317B: OHP/T193 continued follow-up
  25. LIGO/Virgo/KAGRA S250319bu: Identification of a GW compact binary merger candidate
  26. GRB 250317C: SVOM/GRM observation of a long burst
  27. GRB 250317B: Leavitt Observatory optical upper limit
  28. GRB 250309B/AT2025dws: further ATCA observations
  29. GRB 250317B: Mondy AZT-33IK Optical Observations
  30. GRB 250317C: AstroSat CZTI detection
  31. GRB 250317B: NOT optical observations suggest an optical plateau phase
  32. GRB 250317B: GTC/OSIRIS+ spectroscopic redshift z=3.44
  33. GRB 250317C: GECAM-B detection
  34. GRB 250317B: OHP/T193 optical observations
  35. Fermi trigger No 763933627: Global MASTER-Net observations report
  36. GRB250312A: Swift/UVOT Upper Limits
  37. GRB 250317B: REM optical/NIR observations
  38. GRB 250317B: Swift-XRT observations
  39. GRB 250316A: Swift/UVOT Upper Limits
  40. GRB 250314A: REM optical/NIR upper limits
  41. GRB 250316A: AbAO AS-32 Optical Upper Limit
  42. EP 250317B: Fading optical counterpart detection by LCO
  43. GRB 250316A: Swift-XRT afterglow detection
  44. GRB 250317B: LCO detection of the fading optical afterglow
  45. GRB 250317B: refined SVOM/MXT analysis
  46. GRB 250317B: SVOM/VT detection of an optical candidate from VHF data
  47. GRB 250317B: SVOM/F-GFT (COLIBRÍ) Detection of a Fading Optical Counterpart
  48. GRB 250317B: SVOM detection of a burst / correction to GRB name of GCN 39752
  49. GRB 250317B: SVOM detection of a burst
  50. GRB 250316A: Fermi GBM Observation
  51. GRB 250316A: Swift-XRT observations
  52. Fermi trigger No 763862734: Global MASTER-Net observations report
  53. GRB 250317A: Fermi GBM Final Real-time Localization
  54. Fermi GRB 250316A: Global MASTER-Net observations report
  55. GRB 250314A: SVOM/GRM analysis
  56. GRB 250316A: Swift ToO observations
  57. GRB 250316A: Swift/BAT-GUANO arcminute localization of a burst
  58. GRB 250314A: GTC z-band upper limit and updated photo-z ~ 7.27
  59. The EP-WXT trigger 01709132801 is likely a flaring star
  60. GRB 250316A: Fermi GBM Final Real-time Localization
  61. GRB 250315A/EP250315A: Fermi-GBM Sub-Threshold Detection
  62. GRB 250314A: EP-FXT afterglow detection
  63. EP250315a: refined analysis of the EP-WXT and EP-FXT observations
  64. GRB 250314A: Swift/UVOT Upper Limits
  65. GRB 250312B: GRBAlpha detection
  66. GRB 250313.89 / Fermi trigger 763594063: bright OT AT 2025ehi detection
  67. GRB 250314A: Swift XRT Detection
  68. EP250315a: optical counterpart candidate detected by Gemini North
  69. GRB 250314A: VLT/X-shooter dropout, redshift z ~ 7.3
  70. EP250315a: Einstein Probe detection of an X-ray transient
  71. GRB 250226A: Mondy AZT-33IK and Koshka Zeiss-1000 Optical Upper Limits
  72. SVOM/MXT upper limit on GRB 250314A
  73. GRB 250314A: SVOM/VT upper limit
  74. GRB 250314A: NOT near-infrared candidate counterpart
  75. GRB 250313A: Fermi GBM Detection
  76. GRB 250313A: CALET Gamma-Ray Burst Monitor detection
  77. GRB 250312B: Fermi GBM Observation
  78. GRB 250313A: Swift-XRT observations
  79. GRB250314A: SVOM/VT lack of bright optical candidate from VHF data
  80. Konus-Wind detection of GRB 250313A
  81. Konus-Wind detection of GRB 250308A
  82. GRB 250314A: SVOM detection of a burst
  83. EP250311a/GRB 250311A: Correction to EP-WXT detection time
  84. GRB 250313B: SVOM/GRM observation of a soft bright short burst
  85. GRB 250313A: SVOM/GRM observation of a bright long burst
  86. FRB 20250206A: Nondetection of Repeating Bursts from FRB 20250206A with FAST
  87. GRB 250313A: AstroSat CZTI detection 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 250313A: Swift ToO observations
  92. EP250304a: Pan-STARRS r and i-band imaging and photometry
  93. GRB 250312B: Swift/BAT-GUANO localization skymap of a burst
  94. EP trigger ID 01709061302: Lick/Kast spectroscopy with the 3 m Shane telescope
  95. Fermi GRB 250313A: Global MASTER-Net observations report
  96. GRB 250309B: PRIME near-infrared upper limits in 2nd epoch
  97. GRB 250313A???: BALROG localization (Fermi Trigger / GRB 250313607)
  98. GRB 250313A: Fermi GBM Final Real-time Localization
  99. The EP-WXT trigger 01709132551 is not a real source
  100. EP250304a: SVOM/VT optical observation

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