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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"

28303 results found.

  1. GRB 241030B: Nanshan/HMT optical afterglow detection
  2. GRB 241030B: Swift detection of a burst
  3. GRB 240912A: radio detection with the VLA
  4. GRB 241030A: AKO Optical Afterglow Detection
  5. GRB 241030A: Swift/UVOT Detection
  6. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  7. GRB 241026A: Swift-BAT refined analysis
  8. GRB 241030A: SVOM/C-GFT optical observations
  9. GRB 241026A: LBT optical observations
  10. EP241021a: Optical rebrightening observations with Mephisto
  11. GRB 241030A: Multiband optical detection with Mephisto
  12. GRB 241030A: SVOM/VT optical afterglow observations
  13. GRB 241030A : MITSuME Akeno optical afterglow detection
  14. GRB 241030A: Enhanced Swift-XRT position
  15. GRB 241029A: GROWTH-India Telescope optical follow up
  16. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  17. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  18. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  19. GRB 241029A: SAO RAS optical observations
  20. GRB 241026A: SAO RAS optical observations
  21. EP241021a: SAO RAS observations of rebrightening
  22. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  23. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  24. GRB 241026A: Swift/UVOT Upper Limits
  25. GRB 241029A: Swift-XRT observations
  26. GRB 241029A: Fermi GBM Observation
  27. GRB 241029A: AKO Optical Afterglow Detection
  28. EP241021a: continued SOAR observations confirm optical rebrightening
  29. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  30. GRB 241029A: Mephisto observations
  31. EP 241026b: LBT possible optical counterpart (brightening source)
  32. GRB 241029A: TRT optical afterglow candidate detection
  33. GRB 241026A: TNOT optical counterpart detection
  34. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  35. GRB 241025A: further SAO RAS optical observations
  36. GRB 241026A: BTA and Zeiss-1000 optical observations
  37. GRB 241026A: SVOM/GRM observation
  38. EP241026B: GROWTH-India Telescope optical upper limit
  39. GRB 241025A: Swift/UVOT Detection
  40. GRB 241026A: GROWTH-India Telescope optical observations
  41. GRB 241026A Fermi GBM Analysis
  42. GRB 241026A: J-band observations with WINTER
  43. GRB 241025A: SAO RAS optical observations
  44. GRB 241026A: Las Cumbres optical detection
  45. GRB 241025A: Mondy optical observations
  46. EP241021a: SOAR observations of the optical counterpart
  47. EP241021a: further SAO RAS optical observations
  48. GRB 241026A: Swift-XRT refined Analysis
  49. EP 241026b: LBT optical observations
  50. GRB 241026A: Enhanced Swift-XRT position
  51. EP241026b: EP detection of a fast X-ray transient
  52. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  53. GRB 241026A: SAO RAS observations of possible optical afterglow
  54. GRB 241026A: Swift detection of a burst
  55. GRB241025A: 1.3m DFOT optical afterglow detection
  56. EP241021a: optical follow-up observations with Xinglong Observatory
  57. GRB 241025A: GROWTH-India Telescope optical observations
  58. GRB 241025A: COLIBRÍ Detection of the Afterglow
  59. GRB 241025A: Swift-XRT refined Analysis
  60. GRB 241025C: Fermi GBM Detection
  61. GRB 241025A: Fermi GBM Observation
  62. IPN triangulation of GRB 241022A (short/hard)
  63. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  64. EP 241021a: Swift-XRT observations
  65. GRB 241025A : SVOM/VT optical afterglow observations
  66. EP241021a: Liverpool Telescope optical follow-up observations
  67. GRB 241025A: Enhanced Swift-XRT position
  68. GRB 241025A: DDOTI Afterglow detection
  69. GRB 241025A: TRT optical afterglow observation
  70. GRB 241025A: Swift detection of a burst with an optical counterpart
  71. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  72. GRB 241001A: ATCA radio observations
  73. GRB 241010A: VIRT Optical Upper Limit
  74. EP241021a: SAO RAS optical observations
  75. EP241021a: KAIT optical observations
  76. EP241021a: 1.3m DFOT Optical observations
  77. EP241021a: GSP detects optical candidate counterpart
  78. EP241021a: Optical upper limits with Kinder observations
  79. EP241021a: TRT optical observations
  80. GRB 241018A: SVOM/C-GFT optical observations
  81. EP241021a: NOT likely optical counterpart
  82. EP EP241021a: Global MASTER-Net observations report
  83. GRB241017A: 1.3m DFOT optical upper limit
  84. GRB 241018A: 1.3m DFOT Optical upper limit
  85. EP241021a: GOTO optical upper limits
  86. EP241021a: EP detection of a fast X-ray transient
  87. IceCube-Cascade 241019A: Upper limits from a search for additional neutrino events in IceCube
  88. GRB 241018A/sb24101802: Mephisto optical upper limit
  89. GRB 241017A/sb24101702: Mephisto optical upper limit
  90. GRB 241018A: Mondy optical upper limit
  91. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  92. GRB 241018A: GROWTH-India telescope optical upper limit
  93. GRB241018A: XingLong Optical Upper Limit
  94. GRB 241018A: Swift-XRT observations
  95. GRB 241018A: REM optical/NIR upper limits
  96. GRB 241018A: NOT optical observations
  97. GRB 241018A: SVOM/VT follow-up and optical candidate
  98. GRB 241018A: LCO/0.4m optical upper limits
  99. GRB 241006A: VIRT Optical Upper Limit
  100. GRB 240727A: VIRT Optical Upper Limit

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