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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"

32724 results found.

  1. GRB 250317C: AstroSat CZTI detection
  2. GRB 250317B: NOT optical observations suggest an optical plateau phase
  3. GRB 250317B: GTC/OSIRIS+ spectroscopic redshift z=3.44
  4. GRB 250317B: OHP/T193 optical observations
  5. GRB250312A: Swift/UVOT Upper Limits
  6. GRB 250317B: REM optical/NIR observations
  7. GRB 250317B: Swift-XRT observations
  8. GRB 250316A: Swift/UVOT Upper Limits
  9. GRB 250314A: REM optical/NIR upper limits
  10. GRB 250316A: AbAO AS-32 Optical Upper Limit
  11. EP 250317B: Fading optical counterpart detection by LCO
  12. GRB 250317B: LCO detection of the fading optical afterglow
  13. GRB 250317B: refined SVOM/MXT analysis
  14. GRB 250317B: SVOM/VT detection of an optical candidate from VHF data
  15. GRB 250317B: SVOM/F-GFT (COLIBRÍ) Detection of a Fading Optical Counterpart
  16. GRB 250317B: SVOM detection of a burst / correction to GRB name of GCN 39752
  17. GRB 250316A: Fermi GBM Observation
  18. GRB 250316A: Swift-XRT observations
  19. Fermi GRB 250316A: Global MASTER-Net observations report
  20. GRB 250314A: SVOM/GRM analysis
  21. GRB 250316A: Swift ToO observations
  22. GRB 250316A: Swift/BAT-GUANO arcminute localization of a burst
  23. GRB 250314A: GTC z-band upper limit and updated photo-z ~ 7.27
  24. GRB 250315A/EP250315A: Fermi-GBM Sub-Threshold Detection
  25. GRB 250314A: EP-FXT afterglow detection
  26. EP250315a: refined analysis of the EP-WXT and EP-FXT observations
  27. GRB 250314A: Swift/UVOT Upper Limits
  28. GRB 250312B: GRBAlpha detection
  29. GRB 250314A: Swift XRT Detection
  30. EP250315a: optical counterpart candidate detected by Gemini North
  31. GRB 250314A: VLT/X-shooter dropout, redshift z ~ 7.3
  32. GRB 250226A: Mondy AZT-33IK and Koshka Zeiss-1000 Optical Upper Limits
  33. SVOM/MXT upper limit on GRB 250314A
  34. GRB 250314A: SVOM/VT upper limit
  35. GRB 250314A: NOT near-infrared candidate counterpart
  36. GRB 250313A: Fermi GBM Detection
  37. GRB 250313A: CALET Gamma-Ray Burst Monitor detection
  38. GRB 250312B: Fermi GBM Observation
  39. GRB250314A: SVOM/VT lack of bright optical candidate from VHF data
  40. Konus-Wind detection of GRB 250313A
  41. Konus-Wind detection of GRB 250308A
  42. EP250311a/GRB 250311A: Correction to EP-WXT detection time
  43. GRB 250313A: SVOM/GRM observation of a bright long burst
  44. FRB 20250206A: Nondetection of Repeating Bursts from FRB 20250206A with FAST
  45. GRB 250313A: AstroSat CZTI detection of a bright long burst
  46. IceCube-250309A: MASTER detection of J140105.33-091631.6 blazar flare with Zhirkov effect
  47. GRB 250313A: Fermi-LAT detection
  48. GRB 250313A: Swift ToO observations
  49. EP250304a: Pan-STARRS r and i-band imaging and photometry
  50. GRB 250312B: Swift/BAT-GUANO localization skymap of a burst
  51. EP trigger ID 01709061302: Lick/Kast spectroscopy with the 3 m Shane telescope
  52. Fermi GRB 250313A: Global MASTER-Net observations report
  53. GRB 250309B: PRIME near-infrared upper limits in 2nd epoch
  54. EP250304a: SVOM/VT optical observation
  55. EP250311a/GRB 250311A: EP-FXT follow-up observation
  56. ATCA detection of the radio counterpart of GRB 250309B-AT2025dws
  57. EP250302a: Chandra X-ray Detection
  58. Fermi GRB 250312B: Global MASTER-Net observations report
  59. GRB 250226B: Fermi GBM Observation
  60. Swift GRB 250312A: Global MASTER-Net observations report
  61. GRB 250302A: Fermi GBM Observation
  62. GRB 250309B/AT2025dws: Daochen/RC-10 optical counterpart observation
  63. GRB 241213A: VIRT Optical Upper Limit
  64. GRB 241228A: VIRT Optical Upper Limit
  65. GRB 250311A/EP250311a: Optical upper limits with Kinder observations
  66. GRB 250223B: Fermi GBM Observation
  67. GRB 250311A: Swift-XRT observations
  68. GRB 250228A: Fermi GBM Observation
  69. GRB 250309B: 1.3m DFOT Optical observations
  70. IceCube-250309A: Upper limits from a search for additional neutrino events in IceCube
  71. EP250311a: Global MASTER-Net observations report
  72. GRB 250308A: Swift/BAT-GUANO localization skymap of a short burst
  73. GRB 250302A: Swift/BAT-GUANO localization skymap of a burst
  74. GRB 250228A: Swift/BAT-GUANO localization skymap of a likely short burst
  75. GRB 250226B: Swift/BAT-GUANO localization skymap of a likely long GRB
  76. GRB 250226A: Swift/BAT-GUANO localization skymap of a long GRB
  77. GRB 250223B: Swift/BAT-GUANO localization skymap of a short burst
  78. GRB 250309B: PRIME near-infrared detection
  79. EP250304a: Chandra detection
  80. GRB 250225B: Swift-BAT refined analysis
  81. GRB 250311A/EP250311a: TRT optical upper limit
  82. IceCube-250309A: MITSuME Akeno and Seimei/TriCCS optical observations
  83. GRB 250311A: Tiled Swift observations
  84. EP250311a/GRB 250311A: EP-WXT detection
  85. GRB 250308A: CALET Gamma-Ray Burst Monitor detection
  86. GRB 250309B: SVOM/VT optical observation
  87. GRB 250309B / AT2025dws: further SAO RAS optical observations
  88. IceCube-250309A: Upper limits from Fermi-GBM Observations
  89. EP250308a: 1.6m Mephisto optical upper limits
  90. Konus-Wind detection of GRB 250309B
  91. GRB 250309B / AT2025dws: KMTNet-CTIO optical observations
  92. IPN triangulation of GRB 250308A (short)
  93. IPN triangulation of GRB 250309B
  94. IceCube-241224A: MASTER detection of PKS 1217+02 blazar flare with Zhirkov effect
  95. GRB 250309B/AT2025dws : COLIBRÍ Detection of the Optical Counterpart
  96. GRB 250309B: Swift-XRT refined Analysis
  97. GRB 250309B / IceCube-250309A: GECAM-B observations
  98. GRB 250309B / AT2025dws: OSIRIS+/GTC spectroscopy z=1.898
  99. Liverpool Telecope observations of AT 2025dws / GRB 250309B
  100. GRB 250309B / AT2025dws: SAO RAS optical observations

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