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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"

32719 results found.

  1. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  2. GRB 250807A: Swift/UVOT Detection
  3. GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  4. GRB 250806A: SVOM/MXT refined analysis
  5. GRB 250806A: SVOM/ECLAIRs refined analysis
  6. EP250807a: NTT z-band optical upper limit
  7. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  8. GRB 250804B: Insight-HXMT detection
  9. GRB 250807A: SVOM/GRM observation
  10. GRB 250807A: AstroSat CZTI detection of bright long burst
  11. GRB 250806A: NOT z-band upper limit and host galaxy candidate
  12. GRB 250807B: NTT optical observations
  13. EP250807a: EP-WXT detection of a fast X-ray transient
  14. GRB 250807A: SVOM/VT optical observation
  15. EP250806a: Upper limit from Fermi-GBM Observations
  16. GRB 250805A: Kilonova-Catcher optical upper limits
  17. EP250806a:SVOM/VT refined analysis
  18. GRB 250805A: Swift/UVOT Upper Limits
  19. GRB 250806A: Swift/UVOT U-band detection
  20. EP250806a: Liverpool telescope optical upper limit
  21. GRB 250806A: EP-FXT observation
  22. EP#01709198415/EP250806a: Swift-XRT observations
  23. EP250806a: Global MASTER-Net observations report
  24. EP250802a: EP-FXT follow-up observation
  25. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  26. EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
  27. EP250806a: SVOM /VT optical candidate
  28. GRB 250806A: J-band upper limit from WINTER
  29. GRB 250805A: Swift-BAT refined analysis
  30. GRB 250806A: KAIT optical upper limit
  31. GRB 250806A: SVOM/VT refined analysis
  32. EP250806a: COLIBRÍ optical upper limit
  33. GRB 250806A: Kilonova-Catcher optical upper limits
  34. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  35. GRB 250806A: SVOM/VT optical upper limit
  36. GRB 250805A: SVOM/VT optical counterpart
  37. GRB 250805A: ESO/VLT observations
  38. GRB 250805A: TRT optical upper limits
  39. GRB 250804B: Tiled Swift observations
  40. EP250802a: additional Liverpool Telescope upper limits
  41. EP250730a: SVOM/VT optical upper limit
  42. EP250802a: Liverpool Telescope optical upper limits
  43. EP250802a: Global MASTER-Net observations report
  44. EP250802a: GROWTH-India Telescope optical upper limit
  45. LIGO/Virgo/KAGRA S250802dn: Updated Sky localization
  46. LIGO/Virgo/KAGRA S250802dn: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
  48. GRB 250702B: SMA observations
  49. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS candidates
  50. LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
  51. EP250711a: CrAO and Assy optical observations
  52. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  53. EP250730a: Global MASTER-Net observations report
  54. EP250730a: COLIBRÍ optical upper limit
  55. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  56. LIGO/Virgo/KAGRA S250725j: DECam DESGW Epoch 1-2 Candidates
  57. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  58. GRB 250725A: AstroSat CZTI detection
  59. GRB 250727A: EP-FXT follow-up observation
  60. GRB 250725A: PRIME near-infrared observations
  61. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
  62. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  63. GRB: Clarification on Gamma-Ray Burst Naming Convention
  64. GRB 250727A: SVOM/ECLAIRs refined analysis
  65. EP-WXT trigger 01709195487: confirmation of a stellar flare by BOOTES-6 & BOOTES-7
  66. GRB 250728A: COLIBRÍ optical upper limit
  67. GRB 250728A: Fermi GBM Observation
  68. LIGO/Virgo/KAGRA S250727dc: Updated Sky localization
  69. GRB 250728A: Swift ToO observations
  70. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  71. GRB 250727A: AST3-2 Upper limit
  72. LIGO/Virgo/KAGRA S250727cl: Updated Sky localization
  73. GRB 250727A: EP-FXT counterpart detection
  74. GRB250727A: SVOM/VT optical upper limit
  75. LIGO/Virgo/KAGRA S250727dc: Identification of a GW compact binary merger candidate
  76. LIGO/Virgo/KAGRA S250727cl: Identification of a GW compact binary merger candidate
  77. LIGO/Virgo/KAGRA S250725j: DECam GW-MMADS candidates
  78. LIGO/Virgo/KAGRA S250725l: Updated Sky localization
  79. LIGO/Virgo/KAGRA S250726ak: Updated Sky localization
  80. LIGO/Virgo/KAGRA S250726ak: Identification of a GW compact binary merger candidate
  81. GRB 250725A: Fermi GBM Observation
  82. LIGO/Virgo/KAGRA S250725j: Updated Sky localization
  83. GRB 250725A: Swift-BAT refined analysis
  84. Konus-Wind detection of GRB 250725A
  85. GRB 250725A: SVOM/GRM observation
  86. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  87. GRB 250725A: Swift/UVOT Upper Limits
  88. GRB 250725A: Fermi-LAT detection
  89. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  90. GRB 250725A: BOOTES-7 early optical detection
  91. GRB 250725A: SVOM/VT optical candidate
  92. LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate (duplicate submission)
  93. LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate
  94. LIGO/Virgo/KAGRA S250725j: Identification of a GW compact binary merger candidate
  95. EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
  96. SVOM J195836+32283 is not a real source
  97. SVOM J195836+32283/sb25072103: Second VT observation
  98. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  99. GRB 250721A: Fermi GBM Observation
  100. SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits

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