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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').
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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"

21794 results found.

  1. GRB 251013C: JinShan observations of the non-thermal rebrightening of the optical counterpart
  2. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) observations of a strong and late rebrightening of the optical counterpart
  3. sb25101602: Swift-XRT counterpart detection
  4. GRB 251016A: SVOM detection of a short burst
  5. GRB 251014A: Swift-XRT observations
  6. GRB 251014B: PRIME J-band upper limit
  7. GRB 251013C: Kilonova-Catcher optical afterglow detection
  8. GRB 251013D: Swift/UVOT Observations
  9. GRB 251013C: Swift/UVOT Detection
  10. Konus-Wind detection of GRB 251007A
  11. GRB 251013C: detection of a radio counterpart at 15.5GHz
  12. Swift Trigger 1404295: possible GRB 251015A
  13. GRB 251014B: Swift/UVOT Upper Limits
  14. GRB 251014B: VLT/FORS2 Optical Observation
  15. GRB 251014D: Swift/UVOT Upper Limits
  16. GRB 251014D: Swift-XRT afterglow detection
  17. GRB 251013C: MAO/AZT-22 optical observations
  18. GRB 251011B: SVOM/VT optical upper limit
  19. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) further multi-band optical observations
  20. GRB 251013C: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
  21. GRB 251014D: Swift detection of a burst
  22. GRB 251014A: PRIME near-infrared upper limits
  23. GRB 251014A: VLT/FORS2 Optical Observation
  24. GRB 251013C: MarSEC, optical afterglow photometry
  25. GRB 251013C: OHP/T193 optical afterglow photometry and spectroscopy
  26. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  27. GRB 251013C: Bassano Bresciano Observatory optical observations
  28. GRB 251013C: Early and late-time optical counterpart detection by LCO
  29. GRB 251013C: Fermi GBM Observation
  30. GRB 251014A: DDOTI Upper Limit
  31. GRB 251013C NUTTelA-TAO / BSTI Early Measurements
  32. LIGO/Virgo/KAGRA S251014cn: Identification of a GW compact binary merger candidate
  33. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  34. GRB 251013C: Asiago optical observations
  35. GRB 251013C: ABObservatory optical observations
  36. GRB 251014A: SAO RAS optical upper limit
  37. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  38. GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst
  39. GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
  40. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  41. GRB 251013C: DDOTI detection of the optical afterglow
  42. GRB 251013C: SAO RAS optical observations
  43. GRB 251013C: LCO optical afterglow detection
  44. GRB 251013C: LAST detection of optical counterpart
  45. GRB 251013C: SVOM/VT optical observation
  46. GRB 251013C: SVOM detection of a burst
  47. GRB 251013B: SVOM/GRM observation
  48. GRB 251013A: SVOM/GRM observation
  49. GRB 251003A: Mondy optical upper limit
  50. MASTER OT J011025.98-583210.6 : SVOM/VT optical observation
  51. LIGO/Virgo/KAGRA S251013x: Identification of a GW compact binary merger candidate
  52. GRB 251011B inspection: MASTER orphan GRB detection
  53. GRB 251011B: Swift/UVOT Upper Limits
  54. GRB 251011B: SVOM/GRM observation
  55. GRB 251011B: Fermi GBM Observation
  56. GRB 251011B : MASTER optical observations
  57. GRB 251011B: Enhanced Swift-XRT position
  58. GRB 251011B: Swift detection of a burst
  59. GRB 251007B: Swift/UVOT Upper Limits
  60. GRB251007A: Swift/UVOT Detection
  61. GRB 251007A: Swift-BAT refined analysis
  62. GRB 251007A: SVOM/GRM observation
  63. GRB 251007B - SVOM/ECLAIRs refined analysis
  64. SVOM/sb25101004: SVOM detection of a stellar flare
  65. GRB 251002A - SVOM/ECLAIRs refined analysis
  66. GRB 251007B: COLIBRÍ optical upper limit
  67. GRB 250917B: iTelescope T-26 upper limit
  68. GRB 251007A: Enhanced Swift-XRT position
  69. GRB 251007B: Swift-XRT refined Analysis
  70. GRB 251007B: Enhanced Swift-XRT position
  71. GRB 251007A: AKO Optical Upper Limit
  72. GRB 251007A: SVOM/C-GFT optical observations
  73. GRB 251005C: PRIME J-band upper limit
  74. Swift GRB 251007B: Global MASTER-Net observations report
  75. GRB 251007B: SVOM/C-GFT upper limit
  76. GRB 251007B: Swift detection of a burst
  77. GRB 251007A: Swift detection of a burst with an optical counterpart
  78. GRB 250702B/EP250702a: JWST/NIRCam Observations
  79. GRB 251006A: Swift/BAT-GUANO subthreshold detection of a short burst
  80. GRB 251006B: SVOM/GRM observation
  81. GRB 251006B: COLIBRÍ optical upper limit
  82. GRB 251006B/EP251006a: EP-WXT detection
  83. GRB 251005C: SVOM/VT optical fading
  84. GRB 251005C: SVOM/GRM observation of a likely short GRB
  85. LIGO/Virgo/KAGRA S251006dd: Identification of a GW compact binary merger candidate
  86. Fermi GRB 251006B: Global MASTER-Net observations report
  87. GRB 251005C: COLIBRÍ optical observations
  88. GRB 251005C: VLT/X-shooter Imaging
  89. GRB 251003A: LAST optical observations
  90. GRB 251002A: LAST optical observations
  91. GRB 251005C: AstroSat CZTI detection
  92. GRB 251005C: Swift/UVOT Upper Limits
  93. GRB 250902A: MSU cubesats detection
  94. GRB 251005C: Enhanced Swift-XRT position
  95. GRB 251005C: Swift detection of a burst
  96. GRB 251005B: Fermi GBM Final Real-time Localization
  97. GRB 251002A: Mondy/AZT-33IK optical observations
  98. EP251003a: Einstein Probe detection of an X-ray transient
  99. GRB 251003A: J-band detection with WINTER
  100. GRB 251002A: NIR observations with WINTER

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