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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"

37276 results found.

  1. GRB 250317B: SVOM detection of a burst
  2. GRB 250316A: Fermi GBM Observation
  3. GRB 250316A: Swift-XRT observations
  4. GRB 250317A: Fermi GBM Final Real-time Localization
  5. Fermi GRB 250316A: Global MASTER-Net observations report
  6. GRB 250314A: SVOM/GRM analysis
  7. GRB 250316A: Swift ToO observations
  8. GRB 250316A: Swift/BAT-GUANO arcminute localization of a burst
  9. GRB 250314A: GTC z-band upper limit and updated photo-z ~ 7.27
  10. GRB 250316A: Fermi GBM Final Real-time Localization
  11. GRB 250315A/EP250315A: Fermi-GBM Sub-Threshold Detection
  12. GRB 250314A: EP-FXT afterglow detection
  13. GRB 250314A: Swift/UVOT Upper Limits
  14. GRB 250312B: GRBAlpha detection
  15. GRB 250313.89 / Fermi trigger 763594063: bright OT AT 2025ehi detection
  16. GRB 250314A: Swift XRT Detection
  17. GRB 250314A: VLT/X-shooter dropout, redshift z ~ 7.3
  18. GRB 250226A: Mondy AZT-33IK and Koshka Zeiss-1000 Optical Upper Limits
  19. SVOM/MXT upper limit on GRB 250314A
  20. GRB 250314A: SVOM/VT upper limit
  21. GRB 250314A: NOT near-infrared candidate counterpart
  22. GRB 250313A: Fermi GBM Detection
  23. GRB 250313A: CALET Gamma-Ray Burst Monitor detection
  24. GRB 250312B: Fermi GBM Observation
  25. GRB 250313A: Swift-XRT observations
  26. Konus-Wind detection of GRB 250313A
  27. Konus-Wind detection of GRB 250308A
  28. GRB 250314A: SVOM detection of a burst
  29. EP250311a/GRB 250311A: Correction to EP-WXT detection time
  30. GRB 250313B: SVOM/GRM observation of a soft bright short burst
  31. GRB 250313A: SVOM/GRM observation of a bright long burst
  32. GRB 250313A: AstroSat CZTI detection of a bright long burst
  33. GRB 250313A: Fermi-LAT detection
  34. GRB 250313A: Swift ToO observations
  35. GRB 250312B: Swift/BAT-GUANO localization skymap of a burst
  36. EP trigger ID 01709061302: Lick/Kast spectroscopy with the 3 m Shane telescope
  37. Fermi GRB 250313A: Global MASTER-Net observations report
  38. GRB 250309B: PRIME near-infrared upper limits in 2nd epoch
  39. GRB 250313A???: BALROG localization (Fermi Trigger / GRB 250313607)
  40. GRB 250313A: Fermi GBM Final Real-time Localization
  41. EP250311a/GRB 250311A: EP-FXT follow-up observation
  42. ATCA detection of the radio counterpart of GRB 250309B-AT2025dws
  43. GRB 250312A: Swift-XRT refined Analysis
  44. Fermi Gamma-ray Burst Monitor trigger 763509110/250312911 is not a GRB
  45. Fermi GRB 250312B: Global MASTER-Net observations report
  46. GRB 250312A: Enhanced Swift-XRT position
  47. GRB 250312B: Fermi GBM Final Localization
  48. LIGO/Virgo/KAGRA S250304cb: Upper limits from Swift/BAT-GUANO
  49. GRB 250226B: Fermi GBM Observation
  50. Swift GRB 250312A: Global MASTER-Net observations report
  51. GRB 250302A: Fermi GBM Observation
  52. GRB 250309B/AT2025dws: Daochen/RC-10 optical counterpart observation
  53. GRB 250312A: Swift detection of a burst
  54. GRB 241213A: VIRT Optical Upper Limit
  55. GRB 241228A: VIRT Optical Upper Limit
  56. GRB 250311A/EP250311a: Optical upper limits with Kinder observations
  57. GRB 250223B: Fermi GBM Observation
  58. GRB 250311A: Swift-XRT observations
  59. GRB 250228A: Fermi GBM Observation
  60. GRB 250309B: 1.3m DFOT Optical observations
  61. GRB 250308A: Swift/BAT-GUANO localization skymap of a short burst
  62. GRB 250302A: Swift/BAT-GUANO localization skymap of a burst
  63. GRB 250228A: Swift/BAT-GUANO localization skymap of a likely short burst
  64. GRB 250226B: Swift/BAT-GUANO localization skymap of a likely long GRB
  65. GRB 250226A: Swift/BAT-GUANO localization skymap of a long GRB
  66. GRB 250223B: Swift/BAT-GUANO localization skymap of a short burst
  67. GRB 250309B: PRIME near-infrared detection
  68. GRB 250225B: Swift-BAT refined analysis
  69. GRB 250311A/EP250311a: TRT optical upper limit
  70. GRB 250311A: Tiled Swift observations
  71. EP250311a/GRB 250311A: EP-WXT detection
  72. GRB 250308A: CALET Gamma-Ray Burst Monitor detection
  73. GRB 250311B: SVOM detection of a burst
  74. GRB 250309B: SVOM/VT optical observation
  75. GRB 250311A/MAXI J1457-026: MAXI/GSC detection
  76. GRB 250309B / AT2025dws: further SAO RAS optical observations
  77. IceCube-250309A: Upper limits from Fermi-GBM Observations
  78. EP250308a: 1.6m Mephisto optical upper limits
  79. Konus-Wind detection of GRB 250309B
  80. GRB 250309B / AT2025dws: KMTNet-CTIO optical observations
  81. IPN triangulation of GRB 250308A (short)
  82. IPN triangulation of GRB 250309B
  83. GRB 250309B/AT2025dws : COLIBRÍ Detection of the Optical Counterpart
  84. GRB 250309B: Swift-XRT refined Analysis
  85. GRB 250309B / IceCube-250309A: GECAM-B observations
  86. GRB 250309B / AT2025dws: OSIRIS+/GTC spectroscopy z=1.898
  87. Liverpool Telecope observations of AT 2025dws / GRB 250309B
  88. GRB 250309B / AT2025dws: SAO RAS optical observations
  89. GRB 250309B / AT2025dws: Swift-UVOT detection
  90. AT 2025dws, likely optical counterpart of GRB 250309B: LCO confirmation of fast fading
  91. GRB 250309B: Fermi GBM Observation
  92. Fermi GRB 250309B: Global MASTER-Net observations report
  93. Fermi GRB 250309A: Global MASTER-Net observations report
  94. GRB250309B: One candidate counterpart from the Zwicky Transient Facility
  95. IceCube-250309A: No candidates from the Zwicky Transient Facility
  96. Fermi-LAT gamma-ray observations of IceCube-250309A
  97. GRB 250308A: SVOM/GRM detection of QPO in the tail emission
  98. GRB 250309B: Fermi GBM Final Localization
  99. Correction to GCN 39633 - Swift is observing GRB 250309B/IceCube-250309A!
  100. GRB 230509B: Tiled Swift observations

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