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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').
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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"

32689 results found.

  1. GRB 250313A: Fermi GBM Detection
  2. GRB 250313A: CALET Gamma-Ray Burst Monitor detection
  3. GRB 250312B: Fermi GBM Observation
  4. GRB250314A: SVOM/VT lack of bright optical candidate from VHF data
  5. Konus-Wind detection of GRB 250313A
  6. Konus-Wind detection of GRB 250308A
  7. EP250311a/GRB 250311A: Correction to EP-WXT detection time
  8. GRB 250313A: SVOM/GRM observation of a bright long burst
  9. FRB 20250206A: Nondetection of Repeating Bursts from FRB 20250206A with FAST
  10. GRB 250313A: AstroSat CZTI detection of a bright long burst
  11. IceCube-250309A: MASTER detection of J140105.33-091631.6 blazar flare with Zhirkov effect
  12. GRB 250313A: Fermi-LAT detection
  13. GRB 250313A: Swift ToO observations
  14. EP250304a: Pan-STARRS r and i-band imaging and photometry
  15. GRB 250312B: Swift/BAT-GUANO localization skymap of a burst
  16. EP trigger ID 01709061302: Lick/Kast spectroscopy with the 3 m Shane telescope
  17. Fermi GRB 250313A: Global MASTER-Net observations report
  18. GRB 250309B: PRIME near-infrared upper limits in 2nd epoch
  19. EP250304a: SVOM/VT optical observation
  20. EP250311a/GRB 250311A: EP-FXT follow-up observation
  21. ATCA detection of the radio counterpart of GRB 250309B-AT2025dws
  22. EP250302a: Chandra X-ray Detection
  23. Fermi GRB 250312B: Global MASTER-Net observations report
  24. GRB 250226B: Fermi GBM Observation
  25. Swift GRB 250312A: Global MASTER-Net observations report
  26. GRB 250302A: Fermi GBM Observation
  27. GRB 250309B/AT2025dws: Daochen/RC-10 optical counterpart observation
  28. GRB 241213A: VIRT Optical Upper Limit
  29. GRB 241228A: VIRT Optical Upper Limit
  30. GRB 250311A/EP250311a: Optical upper limits with Kinder observations
  31. GRB 250223B: Fermi GBM Observation
  32. GRB 250311A: Swift-XRT observations
  33. GRB 250228A: Fermi GBM Observation
  34. GRB 250309B: 1.3m DFOT Optical observations
  35. IceCube-250309A: Upper limits from a search for additional neutrino events in IceCube
  36. EP250311a: Global MASTER-Net observations report
  37. GRB 250308A: Swift/BAT-GUANO localization skymap of a short burst
  38. GRB 250302A: Swift/BAT-GUANO localization skymap of a burst
  39. GRB 250228A: Swift/BAT-GUANO localization skymap of a likely short burst
  40. GRB 250226B: Swift/BAT-GUANO localization skymap of a likely long GRB
  41. GRB 250226A: Swift/BAT-GUANO localization skymap of a long GRB
  42. GRB 250223B: Swift/BAT-GUANO localization skymap of a short burst
  43. GRB 250309B: PRIME near-infrared detection
  44. EP250304a: Chandra detection
  45. GRB 250225B: Swift-BAT refined analysis
  46. GRB 250311A/EP250311a: TRT optical upper limit
  47. IceCube-250309A: MITSuME Akeno and Seimei/TriCCS optical observations
  48. GRB 250311A: Tiled Swift observations
  49. EP250311a/GRB 250311A: EP-WXT detection
  50. GRB 250308A: CALET Gamma-Ray Burst Monitor detection
  51. GRB 250309B: SVOM/VT optical observation
  52. GRB 250309B / AT2025dws: further SAO RAS optical observations
  53. IceCube-250309A: Upper limits from Fermi-GBM Observations
  54. EP250308a: 1.6m Mephisto optical upper limits
  55. Konus-Wind detection of GRB 250309B
  56. GRB 250309B / AT2025dws: KMTNet-CTIO optical observations
  57. IPN triangulation of GRB 250308A (short)
  58. IPN triangulation of GRB 250309B
  59. IceCube-241224A: MASTER detection of PKS 1217+02 blazar flare with Zhirkov effect
  60. GRB 250309B/AT2025dws : COLIBRÍ Detection of the Optical Counterpart
  61. GRB 250309B: Swift-XRT refined Analysis
  62. GRB 250309B / IceCube-250309A: GECAM-B observations
  63. GRB 250309B / AT2025dws: OSIRIS+/GTC spectroscopy z=1.898
  64. Liverpool Telecope observations of AT 2025dws / GRB 250309B
  65. GRB 250309B / AT2025dws: SAO RAS optical observations
  66. GRB 250309B / AT2025dws: Swift-UVOT detection
  67. AT 2025dws, likely optical counterpart of GRB 250309B: LCO confirmation of fast fading
  68. GRB 250309B: Fermi GBM Observation
  69. Fermi GRB 250309B: Global MASTER-Net observations report
  70. Fermi GRB 250309A: Global MASTER-Net observations report
  71. GRB250309B: One candidate counterpart from the Zwicky Transient Facility
  72. IceCube-250309A: No candidates from the Zwicky Transient Facility
  73. Fermi-LAT gamma-ray observations of IceCube-250309A
  74. GRB 250308A: SVOM/GRM detection of QPO in the tail emission
  75. Correction to GCN 39633 - Swift is observing GRB 250309B/IceCube-250309A!
  76. GRB 230509B: Tiled Swift observations
  77. IceCube-250309A - IceCube observation of a high-energy neutrino candidate track-like event
  78. EP250308a: Global MASTER-Net observations report
  79. EP250308a: GSP optical upper limit
  80. GRB 250306A: EIRSAT-1 GMOD detection
  81. Fermi GRB 250307A: Global MASTER-Net observations report
  82. Konus-Wind detection of GRB 250306A
  83. GRB 250306A: Swift-BAT refined analysis
  84. GRB 250306A: NuSTAR detection of the prompt emission
  85. EP250304a: MeerKAT detection of a possible radio counterpart
  86. IceCube-241016A: MASTER flaring blazar 5BZU J073038.29-320820.2 with Zhirkov effect
  87. GRB 250305A: AstroSat CZTI detection
  88. EP250302a:Xinglong optical observations
  89. GRB 250306A: AstroSat CZTI detection
  90. Swift GRB 250306A: Global MASTER-Net observations report
  91. LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
  92. GRB250101A: Radio upper limits from VLA observations
  93. GRB 250305A: SVOM/GRM observation of a burst
  94. EP250304A: Upper limits from Fermi-GBM Observations
  95. Fermi GRB 250305A: Global MASTER-Net observations report
  96. Fermi-LAT Gamma-ray Observations of IceCube-250302A
  97. EP250302a: Optical Observations at CrAO and SAO RAS
  98. GRB 250219A: SVOM/C-GFT optical upper limit at early phase
  99. EP 250304A: Optical counterpart detection by LCO
  100. EP250302A: 1.3m DFOT optical afterglow detection

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