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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"

24641 results found.

  1. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  2. EP241021a: Upper limit from Konus-Wind observations
  3. GRB 241101A: Swift-BAT refined analysis
  4. GRB 241030A: further SAO RAS optical observations
  5. GRB 241030A: Optical Observations via Virtual Telescope Project
  6. EP241021a: Liverpool Telescope optical follow-up observations
  7. GRB 241030B: Swift-XRT refined Analysis
  8. GRB 241026A: SAO RAS optical observations
  9. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  10. GRB 241101A: Swift detection of a burst
  11. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  12. EP241021a: OHP/T193 optical observations
  13. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  14. GRB 241030B: Montarrenti Observatory optical upper limit
  15. EP241026b: Liverpool Telescope optical follow-up
  16. GRB 241030A: SAO RAS optical observations
  17. GRB 241030A: Fermi GBM Observation
  18. EP241021a: AMI-LA radio detection
  19. GRB 241030B : GIT optical upper limits
  20. GRB 241030B: LCOGT Optical Upper Limits
  21. GRB 241030B: Swift-BAT refined analysis
  22. GRB 241030A: Swift-BAT refined analysis
  23. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  24. GRB 241030B: Swift/UVOT Detection
  25. GRB 241029A: LCO optical detection
  26. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  27. GRB 241030B : MITSuME Akeno optical upper limits
  28. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  29. GRB 241030B: SVOM/VT optical afterglow observations
  30. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  31. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  32. GRB241030B: Fermi GBM Observation
  33. GRB 241030B: BTA observations
  34. GRB 241029A: SVOM/VT optical afterglow observations
  35. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  36. GRB 241030B: Enhanced Swift-XRT position
  37. GRB241030B: GRANDMA/TAROT Upper Limit
  38. GRB 241030A: Swift-XRT refined Analysis
  39. GRB 241030B: SAO RAS optical observations
  40. GRB 241030B: AKO Optical Afterglow Detection
  41. GRB 241030B: Nanshan/HMT optical afterglow detection
  42. GRB 241030B: Swift detection of a burst
  43. GRB 240912A: radio detection with the VLA
  44. GRB 241030A: AKO Optical Afterglow Detection
  45. GRB 241030A: Swift/UVOT Detection
  46. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  47. GRB 241026A: Swift-BAT refined analysis
  48. GRB 241030A: SVOM/C-GFT optical observations
  49. GRB 241026A: LBT optical observations
  50. EP241021a: Optical rebrightening observations with Mephisto
  51. GRB 241030A: Multiband optical detection with Mephisto
  52. GRB 241030A: SVOM/VT optical afterglow observations
  53. GRB 241030A : MITSuME Akeno optical afterglow detection
  54. GRB 241030A: Enhanced Swift-XRT position
  55. GRB 241029A: GROWTH-India Telescope optical follow up
  56. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  57. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  58. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  59. GRB 241029A: SAO RAS optical observations
  60. GRB 241026A: SAO RAS optical observations
  61. EP241021a: SAO RAS observations of rebrightening
  62. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  63. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  64. GRB 241026A: Swift/UVOT Upper Limits
  65. GRB 241029A: Swift-XRT observations
  66. GRB 241029A: Fermi GBM Observation
  67. GRB 241029A: AKO Optical Afterglow Detection
  68. EP241021a: continued SOAR observations confirm optical rebrightening
  69. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  70. GRB 241029A: Mephisto observations
  71. EP 241026b: LBT possible optical counterpart (brightening source)
  72. GRB 241029A: TRT optical afterglow candidate detection
  73. GRB 241026A: TNOT optical counterpart detection
  74. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  75. GRB 241025A: further SAO RAS optical observations
  76. GRB 241026A: BTA and Zeiss-1000 optical observations
  77. GRB 241026A: SVOM/GRM observation
  78. EP241026B: GROWTH-India Telescope optical upper limit
  79. GRB 241025A: Swift/UVOT Detection
  80. GRB 241026A: GROWTH-India Telescope optical observations
  81. GRB 241026A Fermi GBM Analysis
  82. GRB 241026A: J-band observations with WINTER
  83. GRB 241025A: SAO RAS optical observations
  84. GRB 241026A: Las Cumbres optical detection
  85. GRB 241025A: Mondy optical observations
  86. EP241021a: SOAR observations of the optical counterpart
  87. EP241021a: further SAO RAS optical observations
  88. GRB 241026A: Swift-XRT refined Analysis
  89. EP 241026b: LBT optical observations
  90. GRB 241026A: Enhanced Swift-XRT position
  91. EP241026b: EP detection of a fast X-ray transient
  92. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  93. GRB 241026A: SAO RAS observations of possible optical afterglow
  94. GRB 241026A: Swift detection of a burst
  95. GRB241025A: 1.3m DFOT optical afterglow detection
  96. EP241021a: optical follow-up observations with Xinglong Observatory
  97. GRB 241025A: GROWTH-India Telescope optical observations
  98. GRB 241025A: COLIBRÍ Detection of the Afterglow
  99. GRB 241025A: Swift-XRT refined Analysis
  100. GRB 241025C: Fermi GBM Detection

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