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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"

15741 results found.

  1. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  2. GRB 241029A: Mephisto observations
  3. EP 241026b: LBT possible optical counterpart (brightening source)
  4. GRB 241029A: TRT optical afterglow candidate detection
  5. GRB 241029A: SVOM/GRM observation
  6. GRB 240821A: Keck/LRIS spectroscopic observations
  7. EP241021a: Gemini-South detection of optical rebrightening
  8. GRB 241026A: TNOT optical counterpart detection
  9. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  10. GRB 241026A: LBT redshift confirmation
  11. GRB 241025A: further SAO RAS optical observations
  12. GRB 241026A: BTA and Zeiss-1000 optical observations
  13. GRB 241026A: SVOM/GRM observation
  14. EP241026B: GROWTH-India Telescope optical upper limit
  15. GRB 241026A: GROWTH-India Telescope optical observations
  16. GRB 241026A: J-band observations with WINTER
  17. GRB 241025A: SAO RAS optical observations
  18. GRB 241026A: Las Cumbres optical detection
  19. GRB 241025A: Mondy optical observations
  20. EP241021a: SOAR observations of the optical counterpart
  21. EP241021a: further SAO RAS optical observations
  22. EP 241026b: LBT optical observations
  23. EP241021a: e-MERLIN radio observation
  24. GRB 241026A: KAIT optical observations
  25. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  26. GRB 241026A: SAO RAS observations of possible optical afterglow
  27. GRB241025A: 1.3m DFOT optical afterglow detection
  28. EP241021a: optical follow-up observations with Xinglong Observatory
  29. ​GRB 241025A: optical photometry from Konkoly
  30. GRB 241025A: GROWTH-India Telescope optical observations
  31. GRB 241025A: COLIBRÍ Detection of the Afterglow
  32. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  33. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  34. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  35. EP241021a: optical follow-up observations with the Liverpool Telescope
  36. GRB 241025A : SVOM/VT optical afterglow observations
  37. EP241021a: Liverpool Telescope optical follow-up observations
  38. GRB 241001A: JWST spectroscopic identification of a supernova counterpart
  39. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  40. GRB 241025A: TRT optical afterglow observation
  41. GRB 241025A: Swift detection of a burst with an optical counterpart
  42. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  43. GRB 241001A: ATCA radio observations
  44. GRB 241010A: VIRT Optical Upper Limit
  45. EP241021a: VLT/FORS2 redshift z = 0.75
  46. EP241021a: SAO RAS optical observations
  47. EP241021a: KAIT optical observations
  48. EP241021a: EP-FXT follow-up observation update
  49. EP241021a: Optical counterpart observations with the Liverpool Telescope
  50. EP241021a: 1.3m DFOT Optical observations
  51. EP241021a: GSP detects optical candidate counterpart
  52. EP241021a: Optical upper limits with Kinder observations
  53. EP241021a: TRT optical observations
  54. GRB 241018A: SVOM/C-GFT optical observations
  55. EP241021a: NOT likely optical counterpart
  56. GRB241017A: 1.3m DFOT optical upper limit
  57. GRB 241018A: 1.3m DFOT Optical upper limit
  58. GRB 241018A: EP-FXT afterglow detection
  59. EP241021a: GOTO optical upper limits
  60. GRB 241018A/sb24101802: Mephisto optical upper limit
  61. GRB 241017A/sb24101702: Mephisto optical upper limit
  62. GRB 241018A: BOOTES-4/MET optical upper limit
  63. GRB 241018A: Mondy optical upper limit
  64. GRB 241018A: GROWTH-India telescope optical upper limit
  65. GRB241018A: XingLong Optical Upper Limit
  66. GRB 241018A: Swift-XRT observations
  67. GRB 241018A: REM optical/NIR upper limits
  68. GRB 241018A: NOT optical observations
  69. GRB 241017A: SVOM/VT follow-up and optical upper limit
  70. GRB 241018A: SVOM/VT follow-up and optical candidate
  71. GRB 241018A: LCO/0.4m optical upper limits
  72. GRB 241006A: VIRT Optical Upper Limit
  73. GRB 240727A: VIRT Optical Upper Limit
  74. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  75. GRB 241017A: GROWTH-India Telescope optical upper limit
  76. GRB 240916A: radio detection with the VLA
  77. GRB 241009A: LCO optical upper limits
  78. GRB 241009A: GRANDMA optical upper limits
  79. GRB 241010A: JinShan optical observations and potential host galaxy
  80. GRB 241010A: J-band observations with WINTER
  81. GRB 241010A: LCO optical observations
  82. GRB 241010A: Swift detection of a burst with an optical counterpart
  83. GRB 241002B: Swift-XRT afterglow detection
  84. GRB 241002A: NOT optical upper limits
  85. IceCube-241006A: No candidates from the Zwicky Transient Facility
  86. GRB 241006A: GRANDMA optical upper limits
  87. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  88. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  89. GRB 240910A: LBT optical observations
  90. GRB 241006A: Swift/UVOT Upper Limits
  91. GRB 241006A: SVOM/VT follow-up and optical upper limit
  92. GRB 241001A: Swift-XRT afterglow detection
  93. GRB 240930B: SVOM/C-GFT optical upper limit
  94. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  95. GRB 241002B: Swift-XRT observations
  96. GRB 241002C: SVOM/C-GFT optical upper limit
  97. GRB 241002B: PRIME near-infrared detection
  98. GRB 241001A : SVOM/VT optical detection
  99. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  100. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc

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