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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"

14854 results found.

  1. EP-WXT trigger 01709133021: Optical upper limit through Kinder observations
  2. GRB 250322B: NuSTAR detection of the prompt emission and regular dips during the burst
  3. EP250321a: TNOT Observation of Optical Counterpart
  4. FRB 250316A: DDOTI Continued Optical Observations (Third Epoch)
  5. SVOM/sb25032302: SVOM detection of a long X-ray transient
  6. GRB 250322A: AstroSat CZTI detection of a short burst
  7. GRB 250322B: AstroSat CZTI detection of a bright long burst
  8. FRB 20250316A: Kinder optical upper limits of the Einstein Probe candidate X-ray source EP J120944.2+585060
  9. EP250321a: Liverpool Telescope optical follow-up
  10. GRB 250322A: Swift detection of a short burst
  11. FRB 20250316A: detection of a candidate associated X-ray source EP J120944.2+585060 by Einstein Probe
  12. GRB 250225B: GECAM-A detection
  13. GRB 250312A: GECAM-A detection
  14. EP250321a: WFST optical observations
  15. GRB 250320B: NuSTAR detection of the prompt emission from two broad bursts and preliminary analysis
  16. GRB 250321C: Fermi GBM Final Real-time Localization
  17. GRB 250320A: NuSTAR Detection of the Prompt Emission and Preliminary Results
  18. GRB 250320B: Fermi-LAT detection
  19. GRB 250321B: SVOM detection of a sub-threshold transient event
  20. EP 250321A: Optical counterpart detection by LCO.
  21. EP250321a: LCO optical counterpart detection
  22. EP250321a: Swift-XRT detection of an X-ray source
  23. EP250321a: VLT/X-shooter redshift z = 4.368
  24. GRB 250320B: AstroSat CZTI detection
  25. EP250321a: REM optical/NIR afterglow detection
  26. EP250321a: BOOTES-5/JGT optical afterglow detection
  27. EP250321a: TRT optical counterpart detection
  28. EP250321a: Einstein Probe detection of an X-ray transient
  29. GRB 250321A: Swift detection of a burst
  30. GRB 250321A: Fermi GBM Final Real-time Localization
  31. GRB 250320B: Fermi GBM Final Real-time Localization
  32. GRB 250320A: Fermi GBM Final Real-time Localization
  33. FRB 20250316A: Upper limits for gamma-ray transient from Insight-HXMT/HE observations
  34. GRB 250313A: GRBAlpha detection
  35. GRB 250319B: Fermi GBM Final Localization
  36. GRB 250319A: Fermi GBM Final Localization
  37. GRB 250317D: EIRSAT-1 GMOD Detection
  38. EP250302a: VLA observations
  39. GRB 250309B/AT2025dws: further ATCA observations
  40. GRB 250317C: AstroSat CZTI detection
  41. GRB 250317C: GECAM-B detection
  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: SVOM/VT detection of an optical candidate from VHF data
  46. GRB 250317B: SVOM/F-GFT (COLIBRÍ) Detection of a Fading Optical Counterpart
  47. GRB 250317B: SVOM detection of a burst / correction to GRB name of GCN 39752
  48. GRB 250317B: SVOM detection of a burst
  49. GRB 250317A: Fermi GBM Final Real-time Localization
  50. GRB 250314A: GTC z-band upper limit and updated photo-z ~ 7.27
  51. GRB 250316A: Fermi GBM Final Real-time Localization
  52. GRB 250315A/EP250315A: Fermi-GBM Sub-Threshold Detection
  53. GRB 250314A: EP-FXT afterglow detection
  54. GRB 250314A: Swift/UVOT Upper Limits
  55. GRB 250312B: GRBAlpha detection
  56. GRB 250313.89 / Fermi trigger 763594063: bright OT AT 2025ehi detection
  57. GRB 250314A: Swift XRT Detection
  58. EP250315a: Einstein Probe detection of an X-ray transient
  59. GRB 250314A: SVOM/VT upper limit
  60. GRB 250314A: NOT near-infrared candidate counterpart
  61. GRB 250313A: Fermi GBM Detection
  62. GRB 250313A: CALET Gamma-Ray Burst Monitor detection
  63. Konus-Wind detection of GRB 250313A
  64. Konus-Wind detection of GRB 250308A
  65. GRB 250314A: SVOM detection of a burst
  66. EP250311a/GRB 250311A: Correction to EP-WXT detection time
  67. FRB 20250206A: Nondetection of Repeating Bursts from FRB 20250206A with FAST
  68. GRB 250313A: AstroSat CZTI detection of a bright long burst
  69. IceCube-250309A: MASTER detection of J140105.33-091631.6 blazar flare with Zhirkov effect
  70. GRB 250313A: Fermi-LAT detection
  71. EP250304a: Pan-STARRS r and i-band imaging and photometry
  72. GRB 250309B: PRIME near-infrared upper limits in 2nd epoch
  73. GRB 250313A: Fermi GBM Final Real-time Localization
  74. EP250311a/GRB 250311A: EP-FXT follow-up observation
  75. ATCA detection of the radio counterpart of GRB 250309B-AT2025dws
  76. EP250302a: Chandra X-ray Detection
  77. GRB 250312B: Fermi GBM Final Localization
  78. GRB 250312A: Swift detection of a burst
  79. GRB 241213A: VIRT Optical Upper Limit
  80. GRB 241228A: VIRT Optical Upper Limit
  81. GRB 250311A/EP250311a: Optical upper limits with Kinder observations
  82. GRB 250309B: 1.3m DFOT Optical observations
  83. GRB 250309B: PRIME near-infrared detection
  84. EP250304a: Chandra detection
  85. EP250311a/GRB 250311A: EP-WXT detection
  86. GRB 250308A: CALET Gamma-Ray Burst Monitor detection
  87. GRB 250311B: SVOM detection of a burst
  88. GRB 250311A/MAXI J1457-026: MAXI/GSC detection
  89. IceCube-250309A: Upper limits from Fermi-GBM Observations
  90. Konus-Wind detection of GRB 250309B
  91. IPN triangulation of GRB 250308A (short)
  92. IPN triangulation of GRB 250309B
  93. IceCube-241224A: MASTER detection of PKS 1217+02 blazar flare with Zhirkov effect
  94. GRB 250309B/AT2025dws : COLIBRÍ Detection of the Optical Counterpart
  95. GRB 250309B / AT2025dws: Swift-UVOT detection
  96. IceCube-250309A: No candidates from the Zwicky Transient Facility
  97. Fermi-LAT gamma-ray observations of IceCube-250309A
  98. GRB 250308A: SVOM/GRM detection of QPO in the tail emission
  99. GRB 250309B: Fermi GBM Final Localization
  100. IceCube-250309A - IceCube observation of a high-energy neutrino candidate track-like event

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