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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"

21940 results found.

  1. EP 241026b: LBT possible optical counterpart (brightening source)
  2. GRB 241029A: TRT optical afterglow candidate detection
  3. GRB 241026A: the 100th GRB detected by GRBAlpha
  4. GRB 241026A: TNOT optical counterpart detection
  5. Konus-Wind detection of GRB 241025A
  6. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  7. GRB 241025A: further SAO RAS optical observations
  8. GRB 241026A: BTA and Zeiss-1000 optical observations
  9. GRB 241026A: SVOM/GRM observation
  10. EP241026B: GROWTH-India Telescope optical upper limit
  11. GRB 241025A: Swift/UVOT Detection
  12. GRB 241026A: GROWTH-India Telescope optical observations
  13. GRB 241026A: J-band observations with WINTER
  14. GRB 241025A: SAO RAS optical observations
  15. GRB 241026A: Las Cumbres optical detection
  16. GRB 241025A: Mondy optical observations
  17. EP241021a: SOAR observations of the optical counterpart
  18. EP241021a: further SAO RAS optical observations
  19. EP 241026b: LBT optical observations
  20. EP241021a: e-MERLIN radio observation
  21. GRB 241026A: Enhanced Swift-XRT position
  22. EP241026b: EP detection of a fast X-ray transient
  23. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  24. GRB 241026A: SAO RAS observations of possible optical afterglow
  25. GRB 241026A: Swift detection of a burst
  26. GRB241025A: 1.3m DFOT optical afterglow detection
  27. EP241021a: optical follow-up observations with Xinglong Observatory
  28. GRB 241025A: GROWTH-India Telescope optical observations
  29. GRB 241025A: COLIBRÍ Detection of the Afterglow
  30. GRB 241025C: Fermi GBM Detection
  31. IPN triangulation of GRB 241022A (short/hard)
  32. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  33. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  34. GRB 241025A : SVOM/VT optical afterglow observations
  35. EP241021a: Liverpool Telescope optical follow-up observations
  36. GRB 241025A: Enhanced Swift-XRT position
  37. GRB 241025A: DDOTI Afterglow detection
  38. GRB 241025A: TRT optical afterglow observation
  39. GRB 241025A: Swift detection of a burst with an optical counterpart
  40. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  41. GRB 241001A: ATCA radio observations
  42. GRB 241010A: VIRT Optical Upper Limit
  43. EP241021a: SAO RAS optical observations
  44. EP241021a: KAIT optical observations
  45. EP241021a: EP-FXT follow-up observation update
  46. EP241021a: 1.3m DFOT Optical observations
  47. EP241021a: Optical upper limits with Kinder observations
  48. EP241021a: TRT optical observations
  49. GRB 241018A: SVOM/C-GFT optical observations
  50. EP241021a: NOT likely optical counterpart
  51. GRB241017A: 1.3m DFOT optical upper limit
  52. GRB 241018A: 1.3m DFOT Optical upper limit
  53. EP241021a: GOTO optical upper limits
  54. EP241021a: EP detection of a fast X-ray transient
  55. Konus-Wind detection of GRB 241018A
  56. GRB 241018A: SVOM/GRM observation
  57. GRB 241018A/sb24101802: Mephisto optical upper limit
  58. GRB 241017A/sb24101702: Mephisto optical upper limit
  59. GRB 241018A: Mondy optical upper limit
  60. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  61. GRB 241018A: GROWTH-India telescope optical upper limit
  62. GRB241018A: XingLong Optical Upper Limit
  63. GRB 241018A: Swift-XRT observations
  64. GRB 241018A: REM optical/NIR upper limits
  65. GRB 241018A: NOT optical observations
  66. GRB 241018A: SVOM/VT follow-up and optical candidate
  67. GRB 241018A: LCO/0.4m optical upper limits
  68. GRB 241006A: VIRT Optical Upper Limit
  69. GRB 240727A: VIRT Optical Upper Limit
  70. GRB 241018A: X-ray afterglow candidate observed by MXT
  71. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  72. GRB 241017A: GROWTH-India Telescope optical upper limit
  73. GRB241017A: TOO Observations by SVOM/MXT
  74. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  75. GRB 241017A: J-band upper limit from WINTER
  76. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  77. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  78. GRB 240916A: radio detection with the VLA
  79. GRB241013A: REM observations
  80. GRB 241009A: LCO optical upper limits
  81. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  82. GRB 241009A: GRANDMA optical upper limits
  83. GRB 241009A: Swift-XRT afterglow detection
  84. GRB 241010A: JinShan optical observations and potential host galaxy
  85. GRB 241010A: J-band observations with WINTER
  86. GRB 241010A: Enhanced Swift-XRT position
  87. GRB 241010A: LCO optical observations
  88. GRB 241010A: Swift detection of a burst with an optical counterpart
  89. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  90. GRB 241002B: Swift-XRT afterglow detection
  91. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  92. GRB 241002A: NOT optical upper limits
  93. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  94. IceCube-241006A: No candidates from the Zwicky Transient Facility
  95. GRB 241006A: GRANDMA optical upper limits
  96. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  97. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  98. GRB 240910A: LBT optical observations
  99. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  100. GRB 241006A: PRIME near-infrared upper limits

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