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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"

37257 results found.

  1. GRB 250830C: GECAM-B detection
  2. GRB 250830C: AstroSat CZTI detection of a long burst
  3. LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
  4. GRB 250831A (SVOM trigger sb25083102) is likely an outburst from star G 272-61
  5. GRB 250831A: Swift-XRT counterpart detection
  6. GRB 250831A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  7. GRB 250831A: SVOM/VT upper limit with VHF data
  8. GRB 250831A: SVOM detection of a soft burst
  9. GRB 250830B: Swift-XRT observations
  10. EP250830a/GRB 250830B: Einstein Probe detection of an X-ray transient and Swift/XRT follow-up
  11. LIGO/Virgo/KAGRA S250830bp: Coverage and upper limits from MAXI/GSC observations
  12. LIGO/Virgo/KAGRA S250830bp GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  13. GRB 250830B: Swift ToO observations
  14. GRB 250830B: MAXI/GSC detection
  15. GRB 250830A / MAXI J0853+337: MAXI/GSC detection
  16. GRB 250828B: Swift-BAT refined analysis
  17. EP250827a: very early ATLAS detections, starting 43 sec after the EP trigger
  18. LIGO/Virgo/KAGRA S250725j: Observations with the NSF-DOE Vera C. Rubin Observatory
  19. LIGO/Virgo/KAGRA S250818k: MeerKAT detection of an increase in radio flux from AT2025ulz
  20. GRB 250808B: SVOM detection of a burst through offline search
  21. EP250828a: Optical counterpart detection with Kinder observations
  22. Swift GRB 250828B: Global MASTER-Net observations report
  23. EP-WXT trigger 01709200800 : KAIT optical observations
  24. EP250828a: KAIT optical upper limit
  25. GRB 250828B: Swift detection of a burst
  26. EP250828a: Optical upper limit with Kinder observations
  27. GRB 250828A: Fermi GBM Final Localization
  28. GRID detection of GRB 250824A
  29. Fermi GRB 250827A: Global MASTER-Net observations report
  30. EP250827a: GOTO observation of the optical afterglow
  31. GRB 250826A: SVOM/GRM observation
  32. GRB 250827A: Fermi GBM Final Real-time Localization
  33. EP250827A: An optical rebrightening was detected by LCO.
  34. EP250827a / GRB 250827A: MASTER-OAFA OT observation
  35. EP250827a: Gemini-South optical counterpart detection
  36. Fermi GRB 250826A: Global MASTER-Net observations report
  37. GRB 250806A: HiPERCAM/GTC limits on a possible supernova
  38. LIGO/Virgo/KAGRA S250818k: SAO RAS BTA z-band observations of AT2025ulz
  39. Fermi Gamma-ray Burst Monitor trigger 777883624/250826283 is not a GRB
  40. GRB 250826A: Fermi GBM Final Real-time Localization
  41. LIGO/Virgo/KAGRA S250818k: GTC/OSIRIS Confirmation of Rebrightening of AT2025ulz
  42. Fermi GRB 250824B: Global MASTER-Net observations report
  43. GRB 250823A: Swift-BAT refined analysis
  44. GRB 250821B: AstroSat CZTI detection
  45. GRB 250819A: AstroSat CZTI detection
  46. LIGO/Virgo/KAGRA S250818k: MASTER predicovery limits of the AT2025ulz/ZTF25abjmnps KN candidate
  47. GRB 250821B: Insight-HXMT detection
  48. GRB 250823A: Swift-XRT refined Analysis
  49. GRB 250824B: Fermi GBM Final Real-time Localization
  50. GRB 250823A: COLIBRÍ optical observations
  51. GRB 250823A: SVOM/VT optical observation
  52. GRB 250824A: Fermi GBM Final Real-time Localization
  53. GRB 250823A: Swift/UVOT Detection
  54. GRB 250823A: NOT optical observations
  55. LIGO/Virgo/KAGRA S250818k: COLIBRÍ confirmation of rebrightening of AT2025ulz
  56. GRB 250823A: Fermi GBM Observation
  57. GRB 250818B: MeerKAT Detection
  58. GRB 250823A: Enhanced Swift-XRT position
  59. GRB 250823A: LCOGT Optical Detection
  60. GRB 250823A: BOOTES6/DPRT early optical detection
  61. GRB 250823A: Liverpool Telescope optical detection
  62. GRB 250823A: Swift detection of a burst
  63. GRB 250823A: Fermi GBM Final Real-time Localization
  64. Konus-Wind detection of GRB 250821B
  65. LIGO/Virgo/KAGRA S250818k: JinShan optical observations of AT2025ulz
  66. GRB 250806A: Gemini observations of host galaxy candidate
  67. IPN triangulation of GRB 250821B (long/bright)
  68. GRB 250821A: Kilonova-Catcher optical upper limits
  69. EP250821a: Swift/XRT counterpart fading
  70. GRB 250812A: SVOM/ECLAIRs refined analysis
  71. GRB 250821A: Swift-BAT refined analysis
  72. LIGO/Virgo/KAGRA S250818k: Pan-STARRS coverage of the skymap and candidate counterparts
  73. EP250821a: Swift/UVOT further observations.
  74. GRB 250821A: VLT/FORS2 Optical Observation
  75. GRB 250821A: GECAM-B detection
  76. GRB 250821B: SVOM/GRM observation
  77. EP250821a: SVOM/VT optical observation
  78. Fermi GRB 250821B: Global MASTER-Net observations report
  79. GRB 250821A: NOT z-band upper limit
  80. GRB 250821C: Fermi GBM Final Real-time Localization
  81. GRB 250821A: KAIT optical upper limit
  82. LIGO/Virgo/KAGRA S250818k: Continued fading and reddening of AT2025ulz from Keck/LRIS imaging observations
  83. GRB 250821A: Swift-XRT refined Analysis
  84. Swift GRB 250821A: Global MASTER-Net observations report
  85. GRB 250821B: Fermi GBM Detection
  86. GRB 250821B: BALROG localization (Fermi Trigger / GRB 250821672)
  87. GRB 250821B: Fermi GBM Final Localization of a Bright Burst
  88. GRB 250821A: Enhanced Swift-XRT position
  89. GRB 250821A: Swift/UVOT Upper Limits
  90. GRB 250821A: LCOGT Optical Upper Limits
  91. GRB 250814A: CMO SAI and SAO RAS izJ observations.
  92. GRB 250821A: Prompt enhanced Swift-XRT position
  93. GRB 250821A: Swift detection of a burst
  94. GRB 250819A: SVOM/GRM observation of a possible “long” duration type I burst
  95. GRB 250819A: Insight-HXMT detection
  96. GRB 250818B: 10 GHz VLA detection
  97. GRB 250814A: Swift/UVOT Upper Limits
  98. GRB 250813B: Swift/UVOT Upper Limit
  99. IPN triangulation of GRB 250816A (short)
  100. IPN triangulation of GRB 250814C (short)

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