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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"

16162 results found.

  1. GRB 241010A: J-band observations with WINTER
  2. GRB 241010A: LCO optical observations
  3. GRB 241010A: Swift detection of a burst with an optical counterpart
  4. GRB 241002B: Swift-XRT afterglow detection
  5. GRB 241002A: NOT optical upper limits
  6. IceCube-241006A: No candidates from the Zwicky Transient Facility
  7. GRB 241006A: GRANDMA optical upper limits
  8. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  9. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  10. GRB 240910A: LBT optical observations
  11. GRB 241006A: Swift/UVOT Upper Limits
  12. GRB 241006A: SVOM/VT follow-up and optical upper limit
  13. GRB 241001A: Swift-XRT afterglow detection
  14. GRB 240930B: SVOM/C-GFT optical upper limit
  15. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  16. GRB 241002B: Swift-XRT observations
  17. GRB 241002C: SVOM/C-GFT optical upper limit
  18. GRB 241002B: PRIME near-infrared detection
  19. GRB 241001A : SVOM/VT optical detection
  20. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  21. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  22. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  23. GRB 241002C : MITSuME Akeno optical upper limits
  24. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  25. GRB241001A: REM optical/NIR upper limits
  26. GRB 241002A: Swift/UVOT Upper Limits
  27. EP240930a: Liverpool Telescope observations
  28. GRB 241002A: LCOGT Optical Upper Limits
  29. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  30. GRB 241001A: Swift/UVOT Detection
  31. GRB 241001A: VLT/X-shooter redshift
  32. GRB 241002B: GOTO optical counterpart candidate
  33. EP trigger ID 01709064214: GOTO confirms detection as a flare star
  34. GRB 241001A: Swift-XRT observations
  35. GRB241001A: optical afterglow candidate
  36. GRB 241002A: 1.5m OSN optical upper limit
  37. GRB 241001A: BOOTES-6/DPRT optical upper limit
  38. EP240930a : KAIT optical upper limit
  39. EP240930a: GOTO optical upper limits
  40. GRB 240929A : Leavitt Observatory optical upper limit
  41. GRB 240825A: LBT optical observations
  42. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  43. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  44. LIGO/Virgo S240919bn: GOTO optical upper limits
  45. EP240913A/GRB 240913C: AbAO optical upper limit
  46. EP240919a / GRB 240919A: Mondy optical upper limit
  47. EP240913a/GRB 240913C: 1.6m Mephisto observations
  48. EP240918a: SVOM/VT upper limit
  49. EP240919a / GRB 240919A: REM optical and NIR upper limits
  50. EP240919a / GRB 240919A: KAIT optical upper limit
  51. EP240918b and EP240918c: Optical upper limits with Kinder observations
  52. EP240919a: Optical upper limit with Kinder observations
  53. GRB 240910A: radio detection with the VLA
  54. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  55. EP240919a: NOT and Gemini optical observations
  56. EP240919a: GOTO optical upper limits
  57. EP240919a: JinShan optical upper limits
  58. EP240918a: JinShan optical upper limits
  59. EP240918a: YAHPT Optical Upper Limit
  60. EP240918a: Optical upper limits with Kinder observations
  61. EP240918a: GMG Optical Upper Limit
  62. GRB 240916A: NOT optical observation
  63. GRB 240825A: The nature of the afterglow motivates the search of the associated supernova
  64. GRB 240916A: Fermi GBM Observation
  65. GRB 240916A (AT 2024vlp / GOTO24fzn): VLT/X-shooter redshift
  66. GRB 240916A: Swift-XRT afterglow detection
  67. GRB 240916A: JinShan optical decay in one of the two GOTO candidates
  68. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  69. EP240913a/GRB 240913C: KAIT optical upper limit
  70. GRB 240910A: SVOM/VT optical observations
  71. EP240913a: NOT optical upper limits
  72. EP240913a: JinShan optical upper limits
  73. EP240913a: ESO-NTT optical observations
  74. GRB 240914A: ESO-NTT optical observations
  75. GRB 240905E: further NOT optical observations
  76. GRB 240911A: LCO optical observations
  77. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  78. GRB 240911A: GOTO optical limits on Swift/XRT candidates
  79. GRB 240912A: J-band observations with WINTER
  80. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  81. GRB 240912A: NOT optical spectroscopy
  82. Fast X-ray Transient EP240801a: GMRT radio observations
  83. GRB 240912A: Swift detection of a burst with an optical counterpart
  84. GRB 240910A: NOT optical observations
  85. GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
  86. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  87. GRB 240910A: JinShan optical observations
  88. GRB 240910A: GOTO candidate optical counterpart
  89. EP240908a: Optical afterglow confirmation
  90. GRB 240825A: 7DT Optical Upper Limit
  91. GRB 240905E: SVOM/VT optical observations
  92. GRB 240905E: SVOM/VT optical observations (duplicate submission of GCN 37453)
  93. EP240908a: Mondy and AbAO follow-up observations
  94. EP240908a: Updates on the WXT detection result around the trigger time
  95. EP240908a: optical afterglow candidate
  96. EP240908a: TRT optical upper limit
  97. GRB 240905B: GOTO optical upper limits
  98. GRB 240905E: GIT optical upper limit
  99. GRB 240905E: Gaoyazi/GOT optical upper limits
  100. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits

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