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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').
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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"

32756 results found.

  1. GRB 250812A: Swift/UVOT Detection
  2. EP250812a: COLIBRÍ detection of the VT candidate and evidence of flattening
  3. EP250812a: Liverpool Telescope upper limits
  4. EP250812a: SVOM/VT optical counterpart
  5. EP250812a: refined analysis of the EP-WXT and EP-FXT observations
  6. LIGO/Virgo/KAGRA S250813k: Identification of a GW compact binary merger candidate
  7. GRB 250812A: EP-FXT counterpart detection
  8. GRB 250812A: Swift ToO observations
  9. GRB 250807B: Swift-BAT refined analysis
  10. EP 250812a: GOTO optical upper limit
  11. GRB 250812A: Kilonova-Catcher optical afterglow detection
  12. EP250812a: Swift-XRT counterpart detection
  13. GRB 250812A: SVOM/COLIBRÍ (FM-GFT) optical observations
  14. GRB 250812A: SVOM/VT optical afterglow confirmation
  15. GRB 250812A: TRT likely optical counterpart detection
  16. GRB 250809A: Swift-BAT refined analysis
  17. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  18. GRB 250807A: Swift-BAT refined analysis
  19. LIGO/Virgo/KAGRA S250810ck: Updated Sky localization and EM Bright Classification
  20. GRB 250809A: Swift/UVOT Detection
  21. LIGO/Virgo/KAGRA S250810ck: Identification of a GW compact binary merger candidate
  22. Corrected Swift-XRT Refined Analysis of GRB 250809A
  23. GRB 250807B: SVOM/VT optical observation
  24. EP250807a: EP-FXT follow-up observation upper limit
  25. GRB 250809A: LCOGT Optical Upper Limits
  26. GRB 250702B: Chandra X-ray Detection
  27. EP250807a: Global MASTER-Net observations report
  28. Fermi GRB 250808A: Global MASTER-Net observations report
  29. GRB 250808A: VLT X-shooter candidate counterpart
  30. GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  31. GRB 250808A: Fermi GBM Observation
  32. GRB 250807A: SVOM/VT optical continued observation
  33. EP-WXT trigger 01709195487: KAIT confirmation of the stellar flare
  34. GRB 250808A: SVOM detection of a long burst
  35. Konus-Wind detection of GRB 250807A
  36. GRB 250807B: Swift/UVOT Detection
  37. GRB 250807B: Kilonova-Catcher optical afterglow detection
  38. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  39. GRB 250807A: Swift/UVOT Detection
  40. GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  41. GRB 250806A: SVOM/MXT refined analysis
  42. GRB 250806A: SVOM/ECLAIRs refined analysis
  43. EP250807a: NTT z-band optical upper limit
  44. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  45. GRB 250804B: Insight-HXMT detection
  46. GRB 250807A: SVOM/GRM observation
  47. GRB 250807A: AstroSat CZTI detection of bright long burst
  48. GRB 250806A: NOT z-band upper limit and host galaxy candidate
  49. GRB 250807B: NTT optical observations
  50. EP250807a: EP-WXT detection of a fast X-ray transient
  51. GRB 250807A: SVOM/VT optical observation
  52. EP250806a: Upper limit from Fermi-GBM Observations
  53. GRB 250805A: Kilonova-Catcher optical upper limits
  54. EP250806a:SVOM/VT refined analysis
  55. GRB 250805A: Swift/UVOT Upper Limits
  56. GRB 250806A: Swift/UVOT U-band detection
  57. EP250806a: Liverpool telescope optical upper limit
  58. GRB 250806A: EP-FXT observation
  59. EP#01709198415/EP250806a: Swift-XRT observations
  60. EP250806a: Global MASTER-Net observations report
  61. EP250802a: EP-FXT follow-up observation
  62. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  63. EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
  64. EP250806a: SVOM /VT optical candidate
  65. GRB 250806A: J-band upper limit from WINTER
  66. GRB 250805A: Swift-BAT refined analysis
  67. GRB 250806A: KAIT optical upper limit
  68. GRB 250806A: SVOM/VT refined analysis
  69. EP250806a: COLIBRÍ optical upper limit
  70. GRB 250806A: Kilonova-Catcher optical upper limits
  71. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  72. GRB 250806A: SVOM/VT optical upper limit
  73. GRB 250805A: SVOM/VT optical counterpart
  74. GRB 250805A: ESO/VLT observations
  75. GRB 250805A: TRT optical upper limits
  76. GRB 250804B: Tiled Swift observations
  77. EP250802a: additional Liverpool Telescope upper limits
  78. EP250730a: SVOM/VT optical upper limit
  79. EP250802a: Liverpool Telescope optical upper limits
  80. EP250802a: Global MASTER-Net observations report
  81. EP250802a: GROWTH-India Telescope optical upper limit
  82. LIGO/Virgo/KAGRA S250802dn: Updated Sky localization
  83. LIGO/Virgo/KAGRA S250802dn: Identification of a GW compact binary merger candidate
  84. LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
  85. GRB 250702B: SMA observations
  86. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS candidates
  87. LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
  88. EP250711a: CrAO and Assy optical observations
  89. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  90. EP250730a: Global MASTER-Net observations report
  91. EP250730a: COLIBRÍ optical upper limit
  92. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  93. LIGO/Virgo/KAGRA S250725j: DECam DESGW Epoch 1-2 Candidates
  94. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  95. GRB 250725A: AstroSat CZTI detection
  96. GRB 250727A: EP-FXT follow-up observation
  97. GRB 250725A: PRIME near-infrared observations
  98. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
  99. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  100. GRB: Clarification on Gamma-Ray Burst Naming Convention

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