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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"

28283 results found.

  1. GRB 241026A: SAO RAS optical observations
  2. EP241021a: SAO RAS observations of rebrightening
  3. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  4. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  5. GRB 241026A: Swift/UVOT Upper Limits
  6. GRB 241029A: Swift-XRT observations
  7. GRB 241029A: Fermi GBM Observation
  8. GRB 241029A: AKO Optical Afterglow Detection
  9. EP241021a: continued SOAR observations confirm optical rebrightening
  10. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  11. GRB 241029A: Mephisto observations
  12. EP 241026b: LBT possible optical counterpart (brightening source)
  13. GRB 241029A: TRT optical afterglow candidate detection
  14. GRB 241026A: TNOT optical counterpart detection
  15. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  16. GRB 241025A: further SAO RAS optical observations
  17. GRB 241026A: BTA and Zeiss-1000 optical observations
  18. GRB 241026A: SVOM/GRM observation
  19. EP241026B: GROWTH-India Telescope optical upper limit
  20. GRB 241025A: Swift/UVOT Detection
  21. GRB 241026A: GROWTH-India Telescope optical observations
  22. GRB 241026A Fermi GBM Analysis
  23. GRB 241026A: J-band observations with WINTER
  24. GRB 241025A: SAO RAS optical observations
  25. GRB 241026A: Las Cumbres optical detection
  26. GRB 241025A: Mondy optical observations
  27. EP241021a: SOAR observations of the optical counterpart
  28. EP241021a: further SAO RAS optical observations
  29. GRB 241026A: Swift-XRT refined Analysis
  30. EP 241026b: LBT optical observations
  31. GRB 241026A: Enhanced Swift-XRT position
  32. EP241026b: EP detection of a fast X-ray transient
  33. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  34. GRB 241026A: SAO RAS observations of possible optical afterglow
  35. GRB 241026A: Swift detection of a burst
  36. GRB241025A: 1.3m DFOT optical afterglow detection
  37. EP241021a: optical follow-up observations with Xinglong Observatory
  38. GRB 241025A: GROWTH-India Telescope optical observations
  39. GRB 241025A: COLIBRÍ Detection of the Afterglow
  40. GRB 241025A: Swift-XRT refined Analysis
  41. GRB 241025C: Fermi GBM Detection
  42. GRB 241025A: Fermi GBM Observation
  43. IPN triangulation of GRB 241022A (short/hard)
  44. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  45. EP 241021a: Swift-XRT observations
  46. GRB 241025A : SVOM/VT optical afterglow observations
  47. EP241021a: Liverpool Telescope optical follow-up observations
  48. GRB 241025A: Enhanced Swift-XRT position
  49. GRB 241025A: DDOTI Afterglow detection
  50. GRB 241025A: TRT optical afterglow observation
  51. GRB 241025A: Swift detection of a burst with an optical counterpart
  52. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  53. GRB 241001A: ATCA radio observations
  54. GRB 241010A: VIRT Optical Upper Limit
  55. EP241021a: SAO RAS optical observations
  56. EP241021a: KAIT optical observations
  57. EP241021a: 1.3m DFOT Optical observations
  58. EP241021a: GSP detects optical candidate counterpart
  59. EP241021a: Optical upper limits with Kinder observations
  60. EP241021a: TRT optical observations
  61. GRB 241018A: SVOM/C-GFT optical observations
  62. EP241021a: NOT likely optical counterpart
  63. EP EP241021a: Global MASTER-Net observations report
  64. GRB241017A: 1.3m DFOT optical upper limit
  65. GRB 241018A: 1.3m DFOT Optical upper limit
  66. EP241021a: GOTO optical upper limits
  67. EP241021a: EP detection of a fast X-ray transient
  68. IceCube-Cascade 241019A: Upper limits from a search for additional neutrino events in IceCube
  69. GRB 241018A/sb24101802: Mephisto optical upper limit
  70. GRB 241017A/sb24101702: Mephisto optical upper limit
  71. GRB 241018A: Mondy optical upper limit
  72. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  73. GRB 241018A: GROWTH-India telescope optical upper limit
  74. GRB241018A: XingLong Optical Upper Limit
  75. GRB 241018A: Swift-XRT observations
  76. GRB 241018A: REM optical/NIR upper limits
  77. GRB 241018A: NOT optical observations
  78. GRB 241018A: SVOM/VT follow-up and optical candidate
  79. GRB 241018A: LCO/0.4m optical upper limits
  80. GRB 241006A: VIRT Optical Upper Limit
  81. GRB 240727A: VIRT Optical Upper Limit
  82. GRB 241018A: X-ray afterglow candidate observed by MXT
  83. GRB 241017A: Swift-XRT observations
  84. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  85. GRB 241001A: EP-FXT afterglow detection
  86. GRB 241017A: GROWTH-India Telescope optical upper limit
  87. GRB241017A: TOO Observations by SVOM/MXT
  88. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  89. GRB 241017A: J-band upper limit from WINTER
  90. GRB 241016B: SVOM/GRM observation
  91. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  92. GRB 241010A: Swift-BAT refined analysis
  93. GRB 241013B: Fermi GBM Observation
  94. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  95. GRB 241013A: Fermi GBM Observation
  96. GRB 240916A: radio detection with the VLA
  97. GRB241013A: REM observations
  98. GRB 241009A: LCO optical upper limits
  99. Integral GRB241013.04: Global MASTER-Net observations report
  100. LIGO/Virgo/KAGRA S241009em: Updated Sky localization

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