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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"

28123 results found.

  1. GRB 241104A: Swift ToO observations
  2. GRB 241104A: NOT optical non-detection
  3. GRB 241104A: SVOM/VT optical candidate
  4. GRB 241105A: Fermi GBM Final Real-time Localization
  5. EP241104a: EP detection of GRB 241104A X-ray emission
  6. GRB 241010A: host galaxy redshift z = 0.977
  7. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  8. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  9. GRB 241104A: Fermi GBM Final Real-time Localization
  10. GRB 241030A: GRBAlpha detection
  11. EP241101a: EP-FXT observations update
  12. EP241103a: GIT optical upper limit
  13. LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
  14. EP241103a: GOTO optical upper limit
  15. EP241101a: Possible detection of an optical counterpart with FTW
  16. EP241103a: Swift XRT detection and improved X-ray position
  17. EP241101a: OHP/T193 optical observations
  18. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  19. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  20. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  21. EP241103a: GSP optical upper limit
  22. EP241103a: an X-ray transient detected by Einstein Probe
  23. GRB 241029A: GRBAlpha detection
  24. EP241101a: BOOTES-7 optical upper limit
  25. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  26. EP241101a: EP-WXT detection of a fast X-ray transient
  27. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  28. EP241021a: Upper limit from Konus-Wind observations
  29. EP241021a: Liverpool Telescope optical follow-up observations
  30. GRB 241030B: Swift-XRT refined Analysis
  31. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  32. GRB 241101A: Swift detection of a burst
  33. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  34. GRB 241030B: Montarrenti Observatory optical upper limit
  35. EP241026b: Liverpool Telescope optical follow-up
  36. EP241021a: AMI-LA radio detection
  37. GRB 241030B: LCOGT Optical Upper Limits
  38. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  39. GRB 241030B: Swift/UVOT Detection
  40. GRB 241029A: LCO optical detection
  41. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  42. GRB 241030B: SVOM/GRM observation
  43. GRB 241030B : MITSuME Akeno optical upper limits
  44. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  45. GRB 241030B: SVOM/VT optical afterglow observations
  46. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  47. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  48. GRB 241030B: BTA observations
  49. GRB 241029A: SVOM/VT optical afterglow observations
  50. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  51. GRB 241030B: Enhanced Swift-XRT position
  52. GRB 241030B: optical observations from the INAF Asiago Observatory
  53. EP241021a: Swift-UVOT detection
  54. GRB241030B: GRANDMA/TAROT Upper Limit
  55. GRB 241030A: Swift-XRT refined Analysis
  56. GRB 241030B: AKO Optical Afterglow Detection
  57. GRB 241030B: Nanshan/HMT optical afterglow detection
  58. GRB 241030B: SVOM/ECLAIRs detection of a burst
  59. GRB 241030B: Prompt enhanced Swift-XRT position
  60. Konus-Wind detection of GRB 241030A
  61. GRB 241030B: Swift detection of a burst
  62. GRB 241030B: Fermi GBM Final Real-time Localization
  63. GRB 241030A: Fermi-LAT detection
  64. GRB 240912A: radio detection with the VLA
  65. GRB 241030A: AKO Optical Afterglow Detection
  66. GRB 241030A: Swift/UVOT Detection
  67. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  68. GRB 241026A: LBT optical observations
  69. EP241026b: EP-FXT follow-up observation
  70. GRB 241030A: Multiband optical detection with Mephisto
  71. GRB 241030A: SVOM/VT optical afterglow observations
  72. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  73. GRB 241030A : MITSuME Akeno optical afterglow detection
  74. GRB 241030A: Enhanced Swift-XRT position
  75. GRB 241029A: GROWTH-India Telescope optical follow up
  76. GRB 241030A: TRT optical observations
  77. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  78. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  79. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  80. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  81. GRB 241030A: Fermi GBM Final Real-time Localization
  82. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  83. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  84. GRB 241026A: Swift/UVOT Upper Limits
  85. GRB 241029A: Swift-XRT observations
  86. GRB 241029A: AKO Optical Afterglow Detection
  87. GRB 241029A: GOTO optical afterglow detection
  88. GRB 241029A: MASTER early optical counterpart detection
  89. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  90. GRB 241029A: TRT optical afterglow candidate detection
  91. GRB 241029A: Swift ToO observations
  92. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  93. GRB 241029A: Fermi GBM Final Real-time Localization
  94. GRB 240821A: Keck/LRIS spectroscopic observations
  95. EP241021a: Gemini-South detection of optical rebrightening
  96. GRB 241026A: the 100th GRB detected by GRBAlpha
  97. GRB 241026A: TNOT optical counterpart detection
  98. Konus-Wind detection of GRB 241025A
  99. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  100. GRB 241026A: GECAM detection

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