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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"

32579 results found.

  1. IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube
  2. GRB 250813B: NOT observations of the optical afterglow
  3. GRB 250813B: SVOM/VT optical observations
  4. Subject GRB 250813B: SVOM/MXT refined analysis
  5. GRB 250814A: COLIBRÍ optical upper limit
  6. GRB 250813A: AstroSat CZTI detection
  7. LIGO/Virgo/KAGRA S250814bg: Identification of a GW compact binary merger candidate possibly associated with GRB 250814A detected by Fermi GBM and Swift BAT
  8. GRB 250813B: VLT X-shooter spectroscopic redshift z = 1.752
  9. GRB 250814A: DDOTI Optical Upper Limit
  10. GRB 250813B: EP-FXT counterpart detection
  11. Fermi-LAT Gamma-ray Observations of IceCube-250813A
  12. GRB 250813B: Swift-XRT afterglow detection
  13. GRB 250813B: SVOM/COLIBRÍ (FM-GFT) optical observations
  14. GRB 250813B: Ondrejov D50 fast decay
  15. GRB 250813B: SVOM detection of a bright long burst (Correction for GCN 41352).
  16. GRB 250813B: Ondrejov D50 optical afterglow detection
  17. LIGO/Virgo/KAGRA S250813k: Updated Sky localization
  18. EP250812a: Nickel optical upper limit
  19. GRB 250812A: VLT X-shooter spectroscopic redshift confirmation z = 2.571
  20. GRB 250812A: NTT spectroscopic redshift z = 2.57
  21. GRB250812a: STEP/T80S Indication of slow decay of afterglow
  22. EP250812a: NOT, NTT, and GS observations
  23. GRB 250812A: Swift/UVOT Detection
  24. EP250812a: COLIBRÍ detection of the VT candidate and evidence of flattening
  25. EP250812a: Liverpool Telescope upper limits
  26. EP250812a: SVOM/VT optical counterpart
  27. EP250812a: refined analysis of the EP-WXT and EP-FXT observations
  28. LIGO/Virgo/KAGRA S250813k: Identification of a GW compact binary merger candidate
  29. GRB 250812A: EP-FXT counterpart detection
  30. GRB 250812A: Swift ToO observations
  31. GRB 250807B: Swift-BAT refined analysis
  32. EP 250812a: GOTO optical upper limit
  33. GRB 250812A: Kilonova-Catcher optical afterglow detection
  34. EP250812a: Swift-XRT counterpart detection
  35. GRB 250812A: SVOM/COLIBRÍ (FM-GFT) optical observations
  36. GRB 250812A: SVOM/VT optical afterglow confirmation
  37. GRB 250812A: TRT likely optical counterpart detection
  38. GRB 250809A: Swift-BAT refined analysis
  39. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  40. GRB 250807A: Swift-BAT refined analysis
  41. LIGO/Virgo/KAGRA S250810ck: Updated Sky localization and EM Bright Classification
  42. GRB 250809A: Swift/UVOT Detection
  43. LIGO/Virgo/KAGRA S250810ck: Identification of a GW compact binary merger candidate
  44. Corrected Swift-XRT Refined Analysis of GRB 250809A
  45. GRB 250807B: SVOM/VT optical observation
  46. EP250807a: EP-FXT follow-up observation upper limit
  47. GRB 250809A: LCOGT Optical Upper Limits
  48. GRB 250702B: Chandra X-ray Detection
  49. EP250807a: Global MASTER-Net observations report
  50. Fermi GRB 250808A: Global MASTER-Net observations report
  51. GRB 250808A: VLT X-shooter candidate counterpart
  52. GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  53. GRB 250808A: Fermi GBM Observation
  54. GRB 250807A: SVOM/VT optical continued observation
  55. EP-WXT trigger 01709195487: KAIT confirmation of the stellar flare
  56. GRB 250808A: SVOM detection of a long burst
  57. Konus-Wind detection of GRB 250807A
  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 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  63. GRB 250806A: SVOM/MXT refined analysis
  64. GRB 250806A: SVOM/ECLAIRs refined analysis
  65. EP250807a: NTT z-band optical upper limit
  66. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  67. GRB 250804B: Insight-HXMT detection
  68. GRB 250807A: SVOM/GRM observation
  69. GRB 250807A: AstroSat CZTI detection of bright long burst
  70. GRB 250806A: NOT z-band upper limit and host galaxy candidate
  71. GRB 250807B: NTT optical observations
  72. EP250807a: EP-WXT detection of a fast X-ray transient
  73. GRB 250807A: SVOM/VT optical observation
  74. EP250806a: Upper limit from Fermi-GBM Observations
  75. GRB 250805A: Kilonova-Catcher optical upper limits
  76. EP250806a:SVOM/VT refined analysis
  77. GRB 250805A: Swift/UVOT Upper Limits
  78. GRB 250806A: Swift/UVOT U-band detection
  79. EP250806a: Liverpool telescope optical upper limit
  80. GRB 250806A: EP-FXT observation
  81. EP#01709198415/EP250806a: Swift-XRT observations
  82. EP250806a: Global MASTER-Net observations report
  83. EP250802a: EP-FXT follow-up observation
  84. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  85. EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
  86. EP250806a: SVOM /VT optical candidate
  87. GRB 250806A: J-band upper limit from WINTER
  88. GRB 250805A: Swift-BAT refined analysis
  89. GRB 250806A: KAIT optical upper limit
  90. GRB 250806A: SVOM/VT refined analysis
  91. EP250806a: COLIBRÍ optical upper limit
  92. GRB 250806A: Kilonova-Catcher optical upper limits
  93. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  94. GRB 250806A: SVOM/VT optical upper limit
  95. GRB 250805A: SVOM/VT optical counterpart
  96. GRB 250805A: ESO/VLT observations
  97. GRB 250805A: TRT optical upper limits
  98. GRB 250804B: Tiled Swift observations
  99. EP250802a: additional Liverpool Telescope upper limits
  100. EP250730a: SVOM/VT optical upper limit

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