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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

26666 results found.

  1. GRB 251013C: SVOM/VT optical observation
  2. GRB 251013C: SVOM detection of a burst
  3. GRB 251013B: SVOM/GRM observation
  4. GRB 251013A: SVOM/GRM observation
  5. GRB 251003A: Mondy optical upper limit
  6. MASTER OT J011025.98-583210.6 : SVOM/VT optical observation
  7. LIGO/Virgo/KAGRA S251013x: Identification of a GW compact binary merger candidate
  8. GRB 251011B inspection: MASTER orphan GRB detection
  9. GRB 251011B: Swift/UVOT Upper Limits
  10. GRB 251011B: SVOM/GRM observation
  11. GRB 251011B: Swift-XRT refined Analysis
  12. GRB 251011B: Fermi GBM Observation
  13. GRB 251011B : MASTER optical observations
  14. GRB 251011B: Enhanced Swift-XRT position
  15. GRB 251011B: Swift detection of a burst
  16. GRB 251007B: Swift/UVOT Upper Limits
  17. GRB251007A: Swift/UVOT Detection
  18. GRB 251009B (short): Glowbug gamma-ray detection
  19. GRB 251007A: SVOM/GRM observation
  20. GRB 251007B - SVOM/ECLAIRs refined analysis
  21. SVOM/sb25101004: SVOM detection of a stellar flare
  22. GRB 251006A: Fermi GBM Observation
  23. GRB 251002A - SVOM/ECLAIRs refined analysis
  24. GRB 251003A: Fermi GBM Observation
  25. GRB 251006B: Fermi GBM Observation
  26. GRB 251007B: COLIBRÍ optical upper limit
  27. GRB 251007A: AstroSat CZTI detection
  28. GRB 251006B/EP251006a: EP-FXT afterglow detection
  29. GRB 250917B: iTelescope T-26 upper limit
  30. GRB 251007A: Swift-XRT refined Analysis
  31. GRB 251007A: Enhanced Swift-XRT position
  32. GRB 251007B: Swift-XRT refined Analysis
  33. GRB 251007B: Enhanced Swift-XRT position
  34. GRB 251007A: AKO Optical Upper Limit
  35. GRB 251007A: SVOM/C-GFT optical observations
  36. GRB 251005C: PRIME J-band upper limit
  37. GRB 251007A: Glowbug gamma-ray detection
  38. GRB 251007B: SVOM/C-GFT upper limit
  39. GRB 251007B: SVOM detection of a faint burst
  40. GRB 251007B: Swift detection of a burst
  41. GRB 251007A: Swift detection of a burst with an optical counterpart
  42. GRB 250702B/EP250702a: JWST/NIRCam Observations
  43. GRB 251006A: Swift/BAT-GUANO subthreshold detection of a short burst
  44. GRB 251005B: Glowbug gamma-ray detection
  45. GRB 251006B/EP251006a: SVOM/VT optical candidate
  46. GRB 251006B/EP251006a: EP-FXT follow-up observation
  47. GRB 251006B: SVOM/GRM observation
  48. GRB 251006B: COLIBRÍ optical upper limit
  49. GRB 251006B/EP251006a: EP-WXT detection
  50. GRB 251005C: SVOM/VT optical fading
  51. GRB 251005C: SVOM/GRM observation of a likely short GRB
  52. LIGO/Virgo/KAGRA S251006dd: Identification of a GW compact binary merger candidate
  53. GRB 251006A (short): Glowbug gamma-ray detection
  54. GRB 251005C: COLIBRÍ optical observations
  55. GRB 251005C: VLT/X-shooter Imaging
  56. GRB 251003A: LAST optical observations
  57. GRB 251002A: LAST optical observations
  58. GRB 251005C: Swift/UVOT Upper Limits
  59. GRB 250902A: MSU cubesats detection
  60. GRB 251005C: Swift-XRT refined Analysis
  61. GRB 251005C: Fermi GBM Observation
  62. GRB 251005C: Enhanced Swift-XRT position
  63. GRB 251005C: Swift detection of a burst
  64. GRB 251002A: Mondy/AZT-33IK optical observations
  65. EP251003a: Einstein Probe detection of an X-ray transient
  66. GRB 251003A: J-band detection with WINTER
  67. GRB 251002A: NIR observations with WINTER
  68. GRB 251003A: Swift-BAT refined analysis
  69. GRB 251001B: NIR observations with WINTER
  70. GRB 251002A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  71. GRB 251003A: Swift/UVOT Upper Limits
  72. GRB 251002A: Swift/UVOT detection
  73. GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay
  74. GRB 251003A: Swift-XRT refined Analysis
  75. GRB 251002A: Fermi GBM Observation
  76. GRB 251002A: GOTO detection of optical counterpart
  77. GRB 251001C: SVOM/GRM observation
  78. EP250821a: iTelescope T-59 possible detection of the optical counterpart
  79. GRB 251003A: Enhanced Swift-XRT position
  80. GRB 251002A: AKO Early Optical Afterglow Detection
  81. GRB 251003A: Kilonova-Catcher optical afterglow detection
  82. GRB 251002A: Swift-XRT afterglow detection
  83. GRB 251001B: AbAO optical upper limit
  84. GRB 251002A: Kilonova-Catcher optical afterglow detection
  85. GRB 251002A: AbAO optical observations
  86. GRB 251002A: SVOM/COLIBRÍ (FM-GFT) optical observations
  87. GRB 251002A: J band observations by SYSU 80cm infrared telescope
  88. GRB 251002A: OHP/T193 MISTRAL optical afterglow detection
  89. GRB 251003A: LCOGT Optical Detection
  90. GRB 251003A: COLIBRÍ optical detection of the fading afterglow
  91. GRB 251003A: Swift detection of a burst
  92. Fermi/SVOM GRB 251002A : MASTER OT earlier detection in 2 polarization filters
  93. GRB 251002A: BOOTES-6 early optical detection
  94. GRB 251002A: SAO RAS optical observations
  95. GRB 251002A: ULL-ASTRO-MASTER early detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  96. GRB 251002A: LCO optical observation
  97. GRB 251002A: SVOM/VT optical observation
  98. GRB 251002A: SVOM detection of a burst
  99. GRB 251001A: SVOM/GRM observation
  100. GRB 251001B: Swift/UVOT Detection

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