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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.

Advanced Search Examples (click to copy):

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

25899 results found.

  1. GRB 240912A: SVOM/GRM observation
  2. GRB 240911A: Swift-XRT observations
  3. GRB 240912A: J-band observations with WINTER
  4. GRB 240912A: Swift-XRT refined Analysis
  5. GRB 240912A: Fermi GBM Observation
  6. Swift GRB 240912A: Global MASTER-Net observations report
  7. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  8. GRB 240911A: Tiled Swift observations
  9. GRB 240912A: NOT optical spectroscopy
  10. GRB 240912A: Enhanced Swift-XRT position
  11. GRB 240912A: Redshift from OSIRIS+/GTC
  12. GRB 240910A: Redshift from OSIRIS+/GTC
  13. GRB 240912A: Swift detection of a burst with an optical counterpart
  14. GRB 240910A: Fermi GBM Observation
  15. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  16. GRB 240910A: JinShan optical observations
  17. GRB 240910A: GOTO candidate optical counterpart
  18. EP240908a: Optical afterglow confirmation
  19. GRB 240910A: Swift ToO observations
  20. IPN triangulation of GRB 240905B (short)
  21. GRB 240905E: SVOM/VT optical observations
  22. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  23. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  24. EP240908a: optical afterglow candidate
  25. GRB 240905B: GOTO optical upper limits
  26. GRB 240905E: GIT optical upper limit
  27. GRB 240905B: Swift-XRT observations
  28. GRB 240905E: Gaoyazi/GOT optical upper limits
  29. GRB 240905B: Fermi-LAT detection
  30. GRB 240905B: Swift ToO observations
  31. GRB 240905E: J-band observations with WINTER
  32. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  33. GRB 240905E: AKO Optical Upper Limit
  34. GRB 240905E: SVOM/C-GFT optical upper limit
  35. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  36. GRB 240905E: NOT optical upper limits
  37. GRB 240905E: REM optical/NIR upper limits
  38. GRB 240905E: Swift-XRT refined Analysis
  39. GRB 240905E: SVOM/GRM observation
  40. GRB 240905E: LCOGT Optical Upper Limit
  41. GRB 240905E: Swift/UVOT Upper Limits
  42. GRB 240905E: SAO RAS optical upper limit
  43. GRB 240825A: Montarrenti Observatory optical follow-up observations
  44. GRB 240905E: Nanshan/HMT optical upper limit
  45. Swift GRB 240905E: Global MASTER-Net observations report
  46. GRB 240905E: Swift detection of a burst
  47. GRB 240819A: Optical upper limits from TESS
  48. Swift GRB 240904A: Global MASTER-Net observations report
  49. GRB 240904A: Swift detection of a burst
  50. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  51. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  52. GRB 240828A: GECAM detection
  53. GRB 240825A: Magnitude Correction in SVOM/C-GFT Optical Observations
  54. GRB 240825A: MeerLICHT afterglow detection
  55. GRB 240821A: VLT spectroscopic observations
  56. GRB 240825A: TSHAO Optical Upper Limit
  57. GRB240828B: REM optical/NIR upper limits
  58. GRB 240828B: AbAO optical upper limit
  59. GRB 240828B: Mephisto optical upper limit
  60. GRB 240828B: GRANDMA Optical Upper Limit
  61. GRB 240829A: Swift-BAT refined analysis
  62. GRB 240825A: Swift-BAT refined analysis
  63. GRB 240828B: J-band upper limit from WINTER
  64. GRB 240828B: GMG Optical Upper Limit
  65. GRB 240828A: KAIT continued optical observations
  66. GRB 240828B: GWAC-F50A optical upper limit
  67. GRB 240828B: SVOM/C-GFT optical upper limit
  68. GRB 240828B: SAO RAS optical upper limit
  69. GRB 240828B: KAIT optical upper limit
  70. GRB 240828A: Fermi GBM Observation
  71. GRB 240828A: KAIT Optical Afterglow Candidate
  72. GRB 240825A: SVOM/VT optical detection
  73. GRB 240828A: Swift-XRT afterglow detection
  74. GRB 240825A: iTelescope optical observations
  75. GRB 240828B: Swift-XRT afterglow detection
  76. GRB 240829A: Swift detection of a burst
  77. Swift GRB240829.16: Global MASTER-Net observations report
  78. GRB 240828A: Fermi-LAT detection
  79. GRB 240828A: Tiled Swift observations
  80. GRB 240825A: Upper limits from a neutrino search with IceCube
  81. GRB 240819A as a likely X-Ray Flash
  82. GRB 240828B: Swift ToO observations
  83. SVOM GRB 240821A: optical afterglow discovery
  84. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  85. GRB 240825A: GECAM detection
  86. GRB 240824A: GIT optical upper limit
  87. GRB 240819A: Swift afterglow confirmation
  88. GRB 240825A: TNG optical photometry and spectroscopy
  89. GRB 240824B: Ondrejov D50 optical limit
  90. GRB 240825A: KAIT optical observations
  91. GRB 240825A: PRIME near-infrared detection
  92. Konus-Wind detection of GRB 240825A (bright/long)
  93. GRB 240825A: Fermi GBM Observation
  94. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  95. GRB 240825A: AKO Optical Follow-Up Observations
  96. GRB 240825A: AstroSat CZTI detection of the long bright burst
  97. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  98. GRB 240825A: Swift/UVOT Detection
  99. GRB 240825A: REM detection of the optical/NIR afterglow
  100. GRB 240825A: Swift-XRT refined Analysis

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