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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"

21937 results found.

  1. GRB 241213A: Swift detection of a burst
  2. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  3. GRB 241209B: GRANDMA/TRT upper limit
  4. GRB 241212A: SVOM detection of a bright long burst
  5. GRB 241209B: GRBAlpha detection
  6. GRB 241206C: GRBAlpha detection
  7. LIGO/Virgo/KAGRA S241210d: Updated Sky localization and EM Bright Classification
  8. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  9. GRB 241209D: REM optical/NIR upper limits
  10. GRB 241209B: Swift-XRT afterglow detection
  11. LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate
  12. EP241208a: Optical upper limit with Kinder observations
  13. GRB 241209D: AstroSat CZTI detection
  14. LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
  15. LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate
  16. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  17. GRB 241209D: COLIBRÍ detection of the afterglow
  18. GRB 241209A: COLIBRÍ Optical Upper Limit
  19. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  20. GRB 241209A: GRANDMA/TAROT upper limit
  21. GRB 241209B: BOOTES-5 optical upper limit
  22. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  23. GRB 241209A: REM optical/NIR observations
  24. GRB 241209D: Enhanced Swift-XRT position
  25. GRB 241209D: Swift detection of a burst
  26. GRB 241209A: Enhanced Swift-XRT position
  27. GRB 241114B: cubesat Avion detection
  28. GRB 241209A: VLT optical observations
  29. GRB 241209A: GOTO optical upper limits
  30. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  31. EP241208a: EP detection of a fast X-ray transient
  32. GRB 241209A: Swift detection of a short burst
  33. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  34. GRB 241206A: DDOTI Upper Limit on the Afterglow
  35. EP241206a: BOOTES Global Network optical limits
  36. EP241206a: EP detection of a fast X-ray transient
  37. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  38. GRB 241206B: SVOM/ECLAIRs detection of a long soft transient
  39. EP241201a: 1.6m Mephisto Optical Upper Limits
  40. GRB 241204A: COLIBRÍ Optical Upper Limit
  41. EP241202b: KAIT optical upper limit
  42. GRB 241204A: DDOTI Upper Limits on the Afterglow
  43. GRB 241201A: GRBAlpha detection
  44. GRB 241204A: Fermi-LAT detection
  45. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  46. EP241202b: Kinder optical counterpart candidate
  47. Konus-Wind detection of GRB 241130A
  48. EP241201a: BOOTES-5 optical upper limit
  49. EP241202b: EP detection of a fast X-ray transient
  50. EP241201a: NOT optical observations
  51. GRB 241128A: Swift/UVOT Upper Limits
  52. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  53. EP241201a: Kinder optical counterpart candidate
  54. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  55. EP241126a: 1.6m Mephisto Optical Upper Limits
  56. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  57. Konus-Wind detection of GRB 241114B
  58. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  59. GRB 241128A: AbAO optical upper limit
  60. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  61. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  62. GRB 241127A: PRIME near-infrared detection
  63. GRB 241128A: Mondy optical observations
  64. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  65. Swift-XRT observations of IceCube -241127A
  66. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  67. GRB 241128A: Enhanced Swift-XRT position
  68. GRB 241128A: NOT optical observations
  69. GRB 241128A: LCO optical detection
  70. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  71. GRB 241128A: Swift-XRT afterglow detection
  72. GRB 241128A: Swift detection of a burst
  73. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  74. GRB 241127A: Swift/UVOT Detection
  75. GRB 241127A: Enhanced Swift-XRT position
  76. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  77. Swift GRB241127.91: Global MASTER-Net OT detection
  78. EP241126a: WFST Observations
  79. GRB 241127A: Swift detection of a burst with an optical counterpart
  80. Swift GRB241127.91: Global MASTER-Net OT detection
  81. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  82. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  83. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  84. EP241126a: Optical Upper limits with Kinder observations
  85. IPN triangulation of GRB 241114B
  86. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  87. EP241126a: GSP detects optical counterpart
  88. EP241126a: TRT optical counterpart detection
  89. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  90. EP241126a: EP detection of a fast X-ray transient
  91. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  92. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  93. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  94. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  95. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  96. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  97. Konus-Wind detection of GRB 241115D / EP 241115a
  98. LIGO/Virgo/KAGRA S241125n: HCT upper limit
  99. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  100. GRB 241026A: radio detection with the VLA

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