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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"

28109 results found.

  1. GRB 250813B: SVOM/GRM observation
  2. GRB 250814A: P200/WIRC observations of the afterglow candidate
  3. GRB 250814A: possible optical afterglow candidate at Spanish observatories
  4. GRB 250814A: KAIT optical upper limit
  5. GRB 250814A: Swift-XRT refined Analysis
  6. GRB 240814A: Fermi GBM Observation
  7. GRB 250814A: Possible afterglow candidate from P200/WIRC
  8. GRB 250813B: Fermi GBM Observation
  9. GRB 250814A: Optical observations with MDM Hiltner 2.4m telescope
  10. GRB 250814A: J-band upper limit from WINTER
  11. IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube
  12. GRB 250813B: NOT observations of the optical afterglow
  13. GRB 250814A: COLIBRÍ optical upper limit
  14. GRB 250813A: AstroSat CZTI detection
  15. LIGO/Virgo/KAGRA S250814bg: Identification of a GW compact binary merger candidate possibly associated with GRB 250814A detected by Fermi GBM and Swift BAT
  16. GRB 250814A: DDOTI Optical Upper Limit
  17. GRB 250813B: EP-FXT counterpart detection
  18. Fermi-LAT Gamma-ray Observations of IceCube-250813A
  19. GRB 250813B: Swift-XRT afterglow detection
  20. GRB 250814A: Swift detection of a burst coincident with a subthreshold GW trigger
  21. GRB 250813B: SVOM/COLIBRÍ (FM-GFT) optical observations
  22. GRB 250813B: SVOM detection of a bright long burst (Correction for GCN 41352).
  23. GRB 250813B: SVOM detection of a bright long burst
  24. LIGO/Virgo/KAGRA S250813k: NED Galaxies in the 4-Update Localization Volume
  25. LIGO/Virgo/KAGRA S250813k: Updated Sky localization
  26. EP250812a: Nickel optical upper limit
  27. GRB 250812A: VLT X-shooter spectroscopic redshift confirmation z = 2.571
  28. EP250812a: NOT, NTT, and GS observations
  29. GRB 250812A: Swift/UVOT Detection
  30. EP250812a: COLIBRÍ detection of the VT candidate and evidence of flattening
  31. EP250812a: Liverpool Telescope upper limits
  32. EP250812a: refined analysis of the EP-WXT and EP-FXT observations
  33. LIGO/Virgo/KAGRA S250813k: Identification of a GW compact binary merger candidate
  34. GRB 250812A: EP-FXT counterpart detection
  35. GRB 250807B: Swift-BAT refined analysis
  36. EP 250812a: GOTO optical upper limit
  37. GRB 250812A: Kilonova-Catcher optical afterglow detection
  38. EP250812a: Swift-XRT counterpart detection
  39. GRB 250812A: SVOM/COLIBRÍ (FM-GFT) optical observations
  40. EP250812a: Einstein Probe detection of an X-ray transient
  41. GRB 250812A: Swift-XRT afterglow detection
  42. GRB 250812A: TRT likely optical counterpart detection
  43. IceCube-Cascade 250809A: Upper limits from a search for additional neutrino events in IceCube
  44. GRB 250809A: Swift-BAT refined analysis
  45. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  46. GRB 250807A: Swift-BAT refined analysis
  47. LIGO/Virgo/KAGRA S250810ck: Updated Sky localization and EM Bright Classification
  48. GRB 250809A: Swift/UVOT Detection
  49. LIGO/Virgo/KAGRA S250810ck: Identification of a GW compact binary merger candidate
  50. Corrected Swift-XRT Refined Analysis of GRB 250809A
  51. GRB 250809A: Swift-XRT refined Analysis
  52. GRB 250809A: LCOGT Optical Upper Limits
  53. GRB 250808A: VLT X-shooter candidate counterpart
  54. GRB 250809A: Swift detection of a gamma ray burst
  55. GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  56. GRB 250808A: Fermi GBM Observation
  57. GRB 250808A: Swift-XRT candidate counterpart detection
  58. GRB 250807B: Swift/UVOT Detection
  59. GRB 250807B: Kilonova-Catcher optical afterglow detection
  60. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  61. GRB 250807A: Swift/UVOT Detection
  62. GRB 250807A: Swift-XRT refined Analysis
  63. GRB 250806A: SVOM/MXT refined analysis
  64. EP250807a: NTT z-band optical upper limit
  65. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  66. GRB 250807A: SVOM/GRM observation
  67. GRB 250807A: AstroSat CZTI detection of bright long burst
  68. GRB 250807B: Swift-XRT refined Analysis
  69. EP250807a: EP-WXT detection of a fast X-ray transient
  70. EP 250807.979: GOTO optical upper limit
  71. EP250807a: COLIBRÍ optical upper limit
  72. EP250806a: Upper limit from Fermi-GBM Observations
  73. GRB 250807B: Enhanced Swift-XRT position
  74. GRB 250807A: Enhanced Swift-XRT position
  75. IceCube-Cascade 250804A: Upper limits from a search for additional neutrino events in IceCube
  76. GRB 250807B: Swift detection of a burst with an optical counterpart.
  77. GRB 250805A: Kilonova-Catcher optical upper limits
  78. GRB 250805A: Swift/UVOT Upper Limits
  79. GRB 250806A: Swift/UVOT U-band detection
  80. EP250806a: Liverpool telescope optical upper limit
  81. GRB 250807A: Swift detection of a burst with an optical counterpart
  82. EP250802a: EP-FXT follow-up observation
  83. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  84. EP250806a: SVOM /VT optical candidate
  85. GRB 250806A: J-band upper limit from WINTER
  86. GRB 250805A: Swift-BAT refined analysis
  87. GRB 250806A: KAIT optical upper limit
  88. GRB 250806A: Swift-XRT counterpart detection
  89. EP250806a: COLIBRÍ optical upper limit
  90. GRB 250806A: Kilonova-Catcher optical upper limits
  91. EP250806a: Einstein Probe detection of an X-ray transient
  92. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  93. GRB 250806A: SVOM/VT optical upper limit
  94. GRB 250806A: SVOM detection of a soft burst
  95. GRB 250805A: SVOM/VT optical counterpart
  96. GRB 250805A: Swift-XRT refined Analysis
  97. GRB 250804B: Swift-XRT observations
  98. GRB 250805A: Enhanced Swift-XRT position
  99. GRB 250805A: TRT optical upper limits
  100. GRB 250805A: Swift-XRT observations

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