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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

11481 results found.

  1. GRB 250806A: SVOM/ECLAIRs refined analysis
  2. GRB 250807A: AstroSat CZTI detection of bright long burst
  3. GRB 250807B: Swift-XRT refined Analysis
  4. GRB 250806A: EP-FXT observation
  5. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  6. EP250806a: SVOM /VT optical candidate
  7. GRB 250806A: Swift-XRT counterpart detection
  8. EP250806a: Einstein Probe detection of an X-ray transient
  9. GRB 250806A: SVOM detection of a soft burst
  10. GRB 250805A: Swift-XRT refined Analysis
  11. GRB 250804C: AstroSat CZTI detection of a long burst
  12. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  13. GRB 250805A: Swift-XRT observations
  14. Swift GRB250805.26: Global MASTER-Net observations report
  15. Fermi Gamma-ray Burst Monitor trigger 775945985/250803856 is not a GRB
  16. The EP-WXT trigger 01709198251 is likely a flaring star
  17. LIGO/Virgo/KAGRA S250802dn: Identification of a GW compact binary merger candidate
  18. The EP-WXT trigger 01709198202 is likely a flaring star
  19. EP250711a: CrAO and Assy optical observations
  20. EP250730a: Einstein Probe detection of an X-ray transient
  21. LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
  22. LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
  23. LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
  24. GRB 250725A: AstroSat CZTI detection
  25. Fermi trigger No 775387550: Global MASTER-Net observations report
  26. GRB 250727A: Swift-XRT observations
  27. LIGO/Virgo/KAGRA S250727dc: Identification of a GW compact binary merger candidate
  28. LIGO/Virgo/KAGRA S250727cl: Identification of a GW compact binary merger candidate
  29. The EP-WXT trigger 01709195487 is likely a flaring star
  30. GRB 250725A: Swift-XRT refined Analysis
  31. Konus-Wind detection of GRB 250725A
  32. LIGO/Virgo/KAGRA S250725j: NED Galaxies in the 3-Initial Localization Volume
  33. GRB 250725A: Fermi-LAT detection
  34. LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate
  35. GRB 250725A: Swift detection of a burst
  36. Fermi GRB 250725A: Global MASTER-Net observations report
  37. Swift GRB 250725A: Global MASTER-Net observations report
  38. SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits
  39. SVOM J195836+32283/sb25072103: NIR observations with WINTER
  40. GRB 250717B: SVOM/GRM observation
  41. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  42. GRB 250721A: MAXI/GSC detection
  43. GRB 250720B: Fermi GBM Final Localization Correction
  44. GRB 250720A: Fermi GBM Final Localization
  45. Fermi trigger No 774730635: Global MASTER-Net observations report
  46. Fermi Gamma-ray Burst Monitor trigger 774670514/250720094 is not a GRB
  47. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  48. GRB 270713A: Kitab and AbAO Optical Observations
  49. Konus-Wind detection of GRB 250716A
  50. GRB 250716A: Swift-XRT afterglow detection
  51. Fermi GRB 250716A: Global MASTER-Net observations report
  52. GRB 250713A: SVOM/C-GFT upper limit
  53. GRB 250713A: Swift-XRT observations
  54. EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  55. Fermi GRB 250711A: Global MASTER-Net observations report
  56. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  57. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  58. GRB 250702B,D,E/EP250702A: JCMT sub-mm observations at 350 GHz
  59. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  60. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  61. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 4-Update Localization Volume
  62. GRB 250704B / EP250704a: VLA radio detection
  63. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  64. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  65. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  66. GRB 250706B/C: Fermi-LAT detection
  67. IceCube-250706A: Global MASTER-Net observations report
  68. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  69. GRB 250706C: Konus-Wind detection of a very bright GRB ~1200 s before GRB 250706B
  70. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  71. GRB 250706B: refined SVOM/MXT data analysis
  72. GRB 250706A: SAO RAS optical observations
  73. GRB250706B: Swift-XRT counterpart detection
  74. GRB 250706B: iTelescope optical observations
  75. GRB 250706B: SVOM detection of a long burst
  76. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  77. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  78. Konus-Wind detection of GRB 250703A
  79. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  80. Konus-Wind detection of short/hard GRB 250704B/ EP250704a
  81. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  82. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 3-Initial Localization Volume
  83. EP250704a: refined analysis of the EP-WXT and FXT follow-up observations
  84. EP250704a / GRB250704B: Swift-XRT counterpart detection
  85. GRB 250704A: Swift-XRT afterglow detection
  86. Konus-Wind detection of GRB 250702F
  87. EP250704a: COLIBRÍ optical counterpart candidate
  88. EP250704a: Einstein Probe detection of an X-ray transient
  89. LIGO/Virgo/KAGRA S250704ab: Coverage and upper limits from MAXI/GSC observations
  90. GRB 250704A: SVOM detection of a burst
  91. Fermi GRB 250703A: Global MASTER-Net observations report
  92. GRB 250702F: Swift-XRT refined Analysis
  93. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  94. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  95. GRBs 250702B,C,D,E / EP250702a: Konus-Wind detection of a hard X-ray transient activity
  96. EP250702a: Global MASTER-Net observations report
  97. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  98. Fermi GRB 250702C: Global MASTER-Net observations report
  99. Konus-Wind detection of GRB 250627A
  100. LIGO/Virgo/KAGRA S250701bp: Identification of a GW compact binary merger candidate

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