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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"

19715 results found.

  1. EP241021a: Liverpool Telescope optical follow-up observations
  2. GRB 241025A: Enhanced Swift-XRT position
  3. GRB 241025A: DDOTI Afterglow detection
  4. GRB 241025A: TRT optical afterglow observation
  5. GRB 241025A: Swift detection of a burst with an optical counterpart
  6. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  7. GRB 241001A: ATCA radio observations
  8. GRB 241010A: VIRT Optical Upper Limit
  9. EP241021a: SAO RAS optical observations
  10. EP241021a: KAIT optical observations
  11. EP241021a: 1.3m DFOT Optical observations
  12. EP241021a: Optical upper limits with Kinder observations
  13. EP241021a: TRT optical observations
  14. GRB 241018A: SVOM/C-GFT optical observations
  15. EP241021a: NOT likely optical counterpart
  16. GRB241017A: 1.3m DFOT optical upper limit
  17. GRB 241018A: 1.3m DFOT Optical upper limit
  18. EP241021a: GOTO optical upper limits
  19. EP241021a: EP detection of a fast X-ray transient
  20. GRB 241018A/sb24101802: Mephisto optical upper limit
  21. GRB 241017A/sb24101702: Mephisto optical upper limit
  22. GRB 241018A: Mondy optical upper limit
  23. GRB 241018A: GROWTH-India telescope optical upper limit
  24. GRB241018A: XingLong Optical Upper Limit
  25. GRB 241018A: Swift-XRT observations
  26. GRB 241018A: REM optical/NIR upper limits
  27. GRB 241018A: NOT optical observations
  28. GRB 241018A: SVOM/VT follow-up and optical candidate
  29. GRB 241018A: LCO/0.4m optical upper limits
  30. GRB 241018A: Swift ToO observations
  31. GRB 241006A: VIRT Optical Upper Limit
  32. GRB 240727A: VIRT Optical Upper Limit
  33. GRB 241018A: X-ray afterglow candidate observed by MXT
  34. GRB 241018A: Detection of a bright long GRB by SVOM
  35. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  36. GRB 241017A: GROWTH-India Telescope optical upper limit
  37. GRB241017A: TOO Observations by SVOM/MXT
  38. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  39. GRB 241017A: J-band upper limit from WINTER
  40. GRB 241017A: Swift ToO observations
  41. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  42. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  43. GRB 240916A: radio detection with the VLA
  44. GRB241013A: REM observations
  45. GRB 241009A: LCO optical upper limits
  46. GRB 241013B: SVOM/GRM observation
  47. GRB 241009A: GRANDMA optical upper limits
  48. GRB 241009A: Swift-XRT afterglow detection
  49. GRB 241010A: JinShan optical observations and potential host galaxy
  50. GRB 241010A: J-band observations with WINTER
  51. GRB 241010A: Enhanced Swift-XRT position
  52. GRB 241010A: LCO optical observations
  53. GRB 241010A: Swift detection of a burst with an optical counterpart
  54. GRB 241009A: Swift ToO observations
  55. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  56. GRB 241002B: Swift-XRT afterglow detection
  57. GRB 241002A: NOT optical upper limits
  58. GRB 241008A: Fermi GBM Final Real-time Localization
  59. IceCube-241006A: No candidates from the Zwicky Transient Facility
  60. GRB 241006A: GRANDMA optical upper limits
  61. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  62. GRB 240910A: LBT optical observations
  63. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  64. GRB 241006A: Swift-XRT refined Analysis
  65. GRB 241006A: PRIME near-infrared upper limits
  66. GRB 241006A: Swift/UVOT Upper Limits
  67. GRB 241001A: Swift-XRT afterglow detection
  68. GRB 241006A: Enhanced Swift-XRT position
  69. GRB 241006A: Swift detection of a burst
  70. GRB 240930B: SVOM/C-GFT optical upper limit
  71. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  72. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  73. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  74. GRB 241002C: SVOM/C-GFT optical upper limit
  75. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  76. GRB 241002B: Swift ToO observations
  77. GRB 241002B: PRIME near-infrared detection
  78. GRB 241002C: Swift ToO observations
  79. IPN triangulation of GRB 240930B / EP 240930a
  80. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  81. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  82. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  83. GRB 241002C : MITSuME Akeno optical upper limits
  84. GRB241001A: REM optical/NIR upper limits
  85. GRB 241002A: Swift/UVOT Upper Limits
  86. EP240930a: Liverpool Telescope observations
  87. GRB 241002A: LCOGT Optical Upper Limits
  88. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  89. GRB 241001A: Swift/UVOT Detection
  90. GRB 241002B: GOTO optical counterpart candidate
  91. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  92. GRB 240929A: Liverpool Telescope prompt followup observations
  93. GRB241001A: optical afterglow candidate
  94. GRB 241002A: Enhanced Swift-XRT position
  95. GRB 241002A: Swift detection of a burst
  96. GRB 240930B: Fermi GBM Observation
  97. GRB 241001A: Swift ToO observations
  98. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  99. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  100. Fermi-LAT Gamma-ray Observations of IceCube-240929A

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