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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"

15740 results found.

  1. GRB 241025A: LBT optical observations
  2. GRB241105A: Gemini-South Optical Afterglow Detection
  3. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  4. GRB 241105A: Swift/UVOT Detection
  5. EP241101a: CrAO ZTSH optical observations
  6. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  7. GRB 241105A: BOOTES-7 optical detection
  8. GRB 241030A: Mondy optical observations
  9. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  10. GRB 241105A: SVOM/VT optical afterglow observations
  11. GRB 241105A: Swift-XRT afterglow detection
  12. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  13. GRB 240511A: LCO upper limits
  14. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  15. GRB 241104A: NOT optical non-detection
  16. GRB 241105A: GOTO tentative optical counterpart candidate
  17. GRB 241104A: SVOM/VT optical candidate
  18. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  19. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  20. GRB 241010A: host galaxy redshift z = 0.977
  21. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  22. EP241101a: EP-FXT observations update
  23. EP241103a: GIT optical upper limit
  24. EP241021a: OHP/T193 further optical observations
  25. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  26. EP241103a: GOTO optical upper limit
  27. EP241101a: Possible detection of an optical counterpart with FTW
  28. EP241021a: continued SOAR observations
  29. EP241101a: Optical upper limits with Kinder observations
  30. EP241101a: OHP/T193 optical observations
  31. EP241103a: Gemini optical limits
  32. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  33. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  34. EP241103a: GSP optical upper limit
  35. EP241103A: LCO optical observations
  36. EP241101a: BOOTES-7 optical upper limit
  37. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  38. GRB241030A: OHP/T193 optical observations
  39. GRB 241101A: FRAM-ORM optical limit
  40. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  41. GRB 241030A: further SAO RAS optical observations
  42. GRB 241030A: Optical Observations via Virtual Telescope Project
  43. EP241021a: Liverpool Telescope optical follow-up observations
  44. GRB 241026A: SAO RAS optical observations
  45. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  46. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  47. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  48. EP241021a: OHP/T193 optical observations
  49. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  50. GRB 241030B: Montarrenti Observatory optical upper limit
  51. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  52. EP241026b: Liverpool Telescope optical follow-up
  53. GRB 241030A: SAO RAS optical observations
  54. GRB 241030B : GIT optical upper limits
  55. GRB 241030B: LCOGT Optical Upper Limits
  56. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  57. GRB 241030B: Swift/UVOT Detection
  58. GRB 241029A: LCO optical detection
  59. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  60. GRB 241030B: SVOM/GRM observation
  61. GRB 241030B : MITSuME Akeno optical upper limits
  62. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  63. GRB 241030B: SVOM/VT optical afterglow observations
  64. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  65. GRB 241029A: SVOM/VT optical afterglow observations
  66. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  67. GRB 241030B: optical observations from the INAF Asiago Observatory
  68. EP241021a: Swift-UVOT detection
  69. GRB 241030B: SAO RAS optical observations
  70. GRB 241030B: AKO Optical Afterglow Detection
  71. GRB 241030B: Nanshan/HMT optical afterglow detection
  72. GRB 240912A: radio detection with the VLA
  73. GRB 241030A: AKO Optical Afterglow Detection
  74. GRB 241030A: Swift/UVOT Detection
  75. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  76. GRB 241030A: SVOM/GRM observation
  77. GRB 241030A: SVOM/C-GFT optical observations
  78. GRB 241026A: LBT optical observations
  79. EP241021a: Optical rebrightening observations with Mephisto
  80. EP241026b: EP-FXT follow-up observation
  81. GRB 241030A: Multiband optical detection with Mephisto
  82. GRB 241030A: SVOM/VT optical afterglow observations
  83. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  84. GRB 241030A : MITSuME Akeno optical afterglow detection
  85. GRB 241029A: GROWTH-India Telescope optical follow up
  86. GRB 241030A: TRT optical observations
  87. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  88. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  89. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  90. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  91. GRB 241029A: SAO RAS optical observations
  92. GRB 241026A: SAO RAS optical observations
  93. EP241021a: ATCA radio observations
  94. GRB 241026A: Swift/UVOT Upper Limits
  95. GRB 241029A: Swift-XRT observations
  96. GRB 241029A: AKO Optical Afterglow Detection
  97. GRB 241029A: GOTO optical afterglow detection
  98. EP241021a: continued SOAR observations confirm optical rebrightening
  99. GRB 241029A: MASTER early optical counterpart detection
  100. GRB 241029A: Xinglong-2.16m optical afterglow confirmation

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