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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"

41971 results found.

  1. Fermi GRB 250909A: Global MASTER-Net observations report
  2. EP250908c: Einstein Probe detection of an X-ray transient
  3. GRB 250909A: Fermi GBM Final Real-time Localization
  4. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  5. EP#01709240652 (possibly EP250908a): FTW optical and NIR observations
  6. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  7. GRB 250907A: GECAM-B detection
  8. GRB 250905A: Swift-BAT refined analysis
  9. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  10. GRB 250903A: Swift-XRT afterglow detection
  11. LIGO/Virgo/KAGRA S250906ca: Identification of a GW compact binary merger candidate
  12. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  13. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  14. EP250905a: Liverpool Telescope i-band upper limits
  15. LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
  16. EP250905b: EP-FXT follow-up observation
  17. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
  18. EP250905a: Liverpool Telescope observations
  19. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  20. EP250905b: Global MASTER-Net observations report
  21. EP250905b: EP-WXT detection of a fast X-ray transient
  22. EP250905a: FTW one optical and multiple NIR counterpart candidates
  23. GRB 250905A: Swift-XRT refined Analysis
  24. EP250905a: JinShan likely optical counterpart detection
  25. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  26. GRB 250904A: Swift-BAT refined analysis
  27. IceCube Alert 250905.84: Global MASTER-Net observations report
  28. GRB 250905A: Swift/UVOT Upper Limits
  29. EP250905a: Global MASTER-Net observations report
  30. GRB 250901A - SVOM/ECLAIRs refined analysis
  31. EP250905a: Einstein Probe detection of an X-ray transient
  32. GRB 250905B: Fermi GBM Final Localization
  33. GRB 250905A: Enhanced Swift-XRT position
  34. GRB 250904A: Swift/UVOT Detection
  35. GRB 250903A: Swift/UVOT detection
  36. GRB 250904A: Swift-XRT refined Analysis
  37. LIGO/Virgo/KAGRA S250904br: Updated Sky localization
  38. EP detected a brightening of LMXB 1ES 1735-26.9
  39. GRB 250905A: Swift detection of a burst
  40. Swift GRB250905.09: Global MASTER-Net observations report
  41. Swift GRB 250904A: Global MASTER-Net observations report
  42. GRB 250904A: Enhanced Swift-XRT position
  43. IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
  44. GRB 250904A: TRT optical counterpart detection
  45. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
  46. GRB 250902B: CALET Gamma-Ray Burst Monitor detection
  47. GRB 250904A: Prompt enhanced Swift-XRT position
  48. EP250827b: Gemini Spectroscopic Confirmation of AT2025wkm as a Ic-BL Supernova
  49. GRB 250904A: Swift detection of a burst
  50. GRB 250902A: CALET Gamma-Ray Burst Monitor detection
  51. LIGO/Virgo/KAGRA S250904cv: Identification of a GW compact binary merger candidate
  52. GRB 250903A: Swift-XRT observations
  53. EP250903a: Swift-XRT observations
  54. EP#01709201209: Swift-XRT observations
  55. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  56. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  57. EP250903a: refined analysis of the EP-WXT and EP-FXT observations
  58. LIGO/Virgo/KAGRA S250904br: Identification of a GW compact binary merger candidate
  59. GRB 250903A: VLT X-shooter spectroscopic redshift z = 1.590
  60. The EP-WXT trigger 01709201209 is likely a flaring star
  61. LIGO/Virgo/KAGRA S250904ae: Identification of a GW compact binary merger candidate
  62. GRB 250903A: EP-FXT counterpart detection
  63. GRB 250902A: GECAM-B detection
  64. GRB 250903A: LCO optical observation
  65. GRB 250903A: LCO optical afterglow detection
  66. GRB 250903A: SVOM/VT optical confirmation with VHF data
  67. EP250903a: SVOM/VT optical confirmation
  68. EP250901a: Mondy, Assy and SAO RAS optical limits
  69. Subject GRB 250903A: SVOM/MXT afterglow detection
  70. EP250903a: LCO candidate counterpart discovery
  71. GRB 250903A: TRT optical counterpart detection
  72. GRB 250902B: AstroSat CZTI detection
  73. GRB 250903A: SVOM detection of a burst
  74. EP250903a: Global MASTER-Net observations report
  75. EP250903a: TRT optical observations
  76. EP250903a: Einstein Probe detection of an X-ray transient
  77. EP 250827B: Detection of supernova counterpart by LCO.
  78. EP/WXT01709201159: GOTO optical follow-up
  79. EP250827b / AT 2025wkm: TRT optical observations
  80. EP250827b: NOT spectroscopic observations and AT 2025wkm classification as a broad-lined type-Ic supernova
  81. EP250827b: continued Liverpool Telescope observations
  82. GRB 250902B: SVOM/GRM observation
  83. EP250827b: SVOM/VT observation of AT 2025wkm
  84. GRB 250831A (SVOM trigger sb25083102): KAIT confirmation of stellar flare
  85. Fermi GRB 250902B: Global MASTER-Net observations report
  86. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  87. GRB 250902A: Fermi GBM Detection
  88. GRB 250901A: Swift/UVOT Upper Limit
  89. GRB 250902B: Fermi GBM Final Real-time Localization
  90. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  91. GRB 250830B: Swift-XRT afterglow detection
  92. LIGO/Virgo/KAGRA S250902av: 1 counterpart neutrino candidate event from an IceCube neutrino search
  93. EP250827b: Liverpool Telescope observations
  94. GRB 250831A (SVOM trigger sb25083102): confirmation of a stellar flare by SVOM/VT
  95. GRB 250902A: SVOM/GRM observation
  96. EP250828a: Early near-infrared follow-up with MIRAGE on the MDM 1.3m telescope
  97. EP250901a: refined analysis of the EP-WXT and EP-FXT observations
  98. GRB 250901A: EP-FXT follow-up observation
  99. GRB 250901A: NOT optical observations
  100. GRB 250902A: Fermi GBM Final Real-time Localization

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