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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"

16159 results found.

  1. GRB 241112B: GOTO optical upper limits
  2. GRB 241030B: TESS detection of optical counterpart
  3. EP241107a: AbAO optical upper limit
  4. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  5. EP241107A: MASTER optical observations of xray transient
  6. EP241107a: KAIT optical observations
  7. GRB 241030A: TESS observations
  8. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  9. EP241107a: Kinder optical follow-up observations
  10. GRB 241025A: radio detection with the VLA
  11. EP241107a: AKO Optical Afterglow Follow-Up Observations
  12. EP241107a: GSP detects optical counterpart
  13. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  14. GRB 241105A: EP-FXT follow-up observations
  15. EP241107a: FTW Optical and NIR observations of the optical counterpart
  16. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  17. EP241107a: GIT optical observations
  18. EP241107a: SVOM/C-GFT optical observations
  19. EP241107a: AKO Optical Afterglow Detection
  20. GRB 241025A: LBT optical observations
  21. GRB241105A: Gemini-South Optical Afterglow Detection
  22. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  23. GRB 241105A: Swift/UVOT Detection
  24. EP241101a: CrAO ZTSH optical observations
  25. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  26. GRB 241105A: BOOTES-7 optical detection
  27. GRB 241030A: Mondy optical observations
  28. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  29. GRB 241105A: SVOM/VT optical afterglow observations
  30. GRB 241105A: Swift-XRT afterglow detection
  31. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  32. GRB 240511A: LCO upper limits
  33. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  34. GRB 241104A: NOT optical non-detection
  35. GRB 241105A: GOTO tentative optical counterpart candidate
  36. GRB 241104A: SVOM/VT optical candidate
  37. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  38. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  39. GRB 241010A: host galaxy redshift z = 0.977
  40. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  41. EP241101a: EP-FXT observations update
  42. EP241103a: GIT optical upper limit
  43. EP241021a: OHP/T193 further optical observations
  44. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  45. EP241103a: GOTO optical upper limit
  46. EP241101a: Possible detection of an optical counterpart with FTW
  47. EP241021a: continued SOAR observations
  48. EP241101a: Optical upper limits with Kinder observations
  49. EP241101a: OHP/T193 optical observations
  50. EP241103a: Gemini optical limits
  51. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  52. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  53. EP241103a: GSP optical upper limit
  54. EP241103A: LCO optical observations
  55. EP241101a: BOOTES-7 optical upper limit
  56. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  57. GRB241030A: OHP/T193 optical observations
  58. GRB 241101A: FRAM-ORM optical limit
  59. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  60. GRB 241030A: further SAO RAS optical observations
  61. GRB 241030A: Optical Observations via Virtual Telescope Project
  62. EP241021a: Liverpool Telescope optical follow-up observations
  63. GRB 241026A: SAO RAS optical observations
  64. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  65. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  66. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  67. EP241021a: OHP/T193 optical observations
  68. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  69. GRB 241030B: Montarrenti Observatory optical upper limit
  70. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  71. EP241026b: Liverpool Telescope optical follow-up
  72. GRB 241030A: SAO RAS optical observations
  73. GRB 241030B : GIT optical upper limits
  74. GRB 241030B: LCOGT Optical Upper Limits
  75. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  76. GRB 241030B: Swift/UVOT Detection
  77. GRB 241029A: LCO optical detection
  78. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  79. GRB 241030B: SVOM/GRM observation
  80. GRB 241030B : MITSuME Akeno optical upper limits
  81. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  82. GRB 241030B: SVOM/VT optical afterglow observations
  83. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  84. GRB 241029A: SVOM/VT optical afterglow observations
  85. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  86. GRB 241030B: optical observations from the INAF Asiago Observatory
  87. EP241021a: Swift-UVOT detection
  88. GRB 241030B: SAO RAS optical observations
  89. GRB 241030B: AKO Optical Afterglow Detection
  90. GRB 241030B: Nanshan/HMT optical afterglow detection
  91. GRB 240912A: radio detection with the VLA
  92. GRB 241030A: AKO Optical Afterglow Detection
  93. GRB 241030A: Swift/UVOT Detection
  94. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  95. GRB 241030A: SVOM/GRM observation
  96. GRB 241030A: SVOM/C-GFT optical observations
  97. GRB 241026A: LBT optical observations
  98. EP241021a: Optical rebrightening observations with Mephisto
  99. EP241026b: EP-FXT follow-up observation
  100. GRB 241030A: Multiband optical detection with Mephisto

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