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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"

42526 results found.

  1. GRB 250910B: Fermi GBM Final Real-time Localization
  2. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  3. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  4. GRB 250909B: AstroSat CZTI detection of a long burst
  5. GRB 250910A: SVOM/VT optical upper limit
  6. EP250908C: GROND observation of the fading optical counterpart
  7. GRB 250910A: LCO optical upper limit
  8. GRB 250909A: AstroSat CZTI detection
  9. GRB 250910A: SVOM/MXT possible afterglow detection
  10. GRB 250910A: SVOM detection of a faint burst
  11. LIGO/Virgo/KAGRA S250910b: Retraction of GW compact binary merger candidate
  12. GRB 250702B: Late time Chandra observations
  13. EP#01709240653: Swift-XRT observations
  14. The EP-WXT trigger 01709240674 is triggered by the known source SS Cyg
  15. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  16. GRB 250907A: CALET Gamma-Ray Burst Monitor detection
  17. EP250908c: SVOM/VT optical observation
  18. EP250908c: VLT/FORS2 optical counterpart identification
  19. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  20. EP250908b: SVOM/VT optical candidate
  21. EP250908c: Global MASTER-Net observations report
  22. Fermi GRB 250909A: Global MASTER-Net observations report
  23. EP250908c: Einstein Probe detection of an X-ray transient
  24. GRB 250909A: Fermi GBM Final Real-time Localization
  25. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  26. EP#01709240652 (possibly EP250908a): FTW optical and NIR observations
  27. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  28. GRB 250907A: GECAM-B detection
  29. GRB 250905A: Swift-BAT refined analysis
  30. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  31. GRB 250903A: Swift-XRT afterglow detection
  32. LIGO/Virgo/KAGRA S250906ca: Identification of a GW compact binary merger candidate
  33. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  34. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  35. EP250905a: Liverpool Telescope i-band upper limits
  36. LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
  37. EP250905b: EP-FXT follow-up observation
  38. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
  39. EP250905a: Liverpool Telescope observations
  40. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  41. EP250905b: Global MASTER-Net observations report
  42. EP250905b: EP-WXT detection of a fast X-ray transient
  43. EP250905a: FTW one optical and multiple NIR counterpart candidates
  44. GRB 250905A: Swift-XRT refined Analysis
  45. EP250905a: JinShan likely optical counterpart detection
  46. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  47. GRB 250904A: Swift-BAT refined analysis
  48. IceCube Alert 250905.84: Global MASTER-Net observations report
  49. GRB 250905A: Swift/UVOT Upper Limits
  50. EP250905a: Global MASTER-Net observations report
  51. GRB 250901A - SVOM/ECLAIRs refined analysis
  52. EP250905a: Einstein Probe detection of an X-ray transient
  53. GRB 250905B: Fermi GBM Final Localization
  54. GRB250904A: Liverpool Telescope upper limits
  55. GRB 250905A: Enhanced Swift-XRT position
  56. GRB 250904A: Swift/UVOT Detection
  57. GRB 250903A: Swift/UVOT detection
  58. GRB 250904A: Swift-XRT refined Analysis
  59. LIGO/Virgo/KAGRA S250904br: Updated Sky localization
  60. EP detected a brightening of LMXB 1ES 1735-26.9
  61. GRB 250905A: KAIT optical upper limit
  62. GRB 250905A: Swift detection of a burst
  63. Swift GRB250905.09: Global MASTER-Net observations report
  64. Swift GRB 250904A: Global MASTER-Net observations report
  65. GRB 250904A: Enhanced Swift-XRT position
  66. IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
  67. GRB 250904A: TRT optical counterpart detection
  68. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
  69. GRB 250902B: CALET Gamma-Ray Burst Monitor detection
  70. GRB 250904A: Prompt enhanced Swift-XRT position
  71. EP250827b: Gemini Spectroscopic Confirmation of AT2025wkm as a Ic-BL Supernova
  72. GRB 250904A: Swift detection of a burst
  73. GRB 250902A: CALET Gamma-Ray Burst Monitor detection
  74. LIGO/Virgo/KAGRA S250904cv: Identification of a GW compact binary merger candidate
  75. GRB 250903A: Swift-XRT observations
  76. EP250903a: Swift-XRT observations
  77. EP#01709201209: Swift-XRT observations
  78. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  79. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  80. EP250903a: refined analysis of the EP-WXT and EP-FXT observations
  81. LIGO/Virgo/KAGRA S250904br: Identification of a GW compact binary merger candidate
  82. GRB 250903A: VLT X-shooter spectroscopic redshift z = 1.590
  83. The EP-WXT trigger 01709201209 is likely a flaring star
  84. LIGO/Virgo/KAGRA S250904ae: Identification of a GW compact binary merger candidate
  85. GRB 250903A: EP-FXT counterpart detection
  86. GRB 250902A: GECAM-B detection
  87. GRB 250903A: LCO optical observation
  88. GRB 250903A: LCO optical afterglow detection
  89. GRB 250903A: SVOM/VT optical confirmation with VHF data
  90. EP250903a: SVOM/VT optical confirmation
  91. EP250901a: Mondy, Assy and SAO RAS optical limits
  92. Subject GRB 250903A: SVOM/MXT afterglow detection
  93. EP250903a: LCO candidate counterpart discovery
  94. GRB 250903A: TRT optical counterpart detection
  95. GRB 250902B: AstroSat CZTI detection
  96. GRB 250903A: SVOM detection of a burst
  97. EP250903a: Global MASTER-Net observations report
  98. EP250903a: TRT optical observations
  99. EP250903a: Einstein Probe detection of an X-ray transient
  100. EP 250827B: Detection of supernova counterpart by LCO.

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