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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"

38929 results found.

  1. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  2. EP241201a: Global MASTER-Net observations report
  3. GRB 241127B: detection of a long GRB by SVOM/ECLAIRs
  4. GRB241201B: Fermi GBM Final Localization
  5. GRB241201B: Fermi GBM Final Localization
  6. Fermi GRB 241201A: Global MASTER-Net observations report
  7. GRB 241201A: BALROG localization (Fermi Trigger 754757764 / GRB 241201622)
  8. GRB 241130A: Fermi GBM Final Real-time Localization
  9. GRB 241130A: Fermi GBM Final Real-time Localization
  10. EP241126a: 1.6m Mephisto Optical Upper Limits
  11. GRB 241201A: Fermi GBM Final Real-time Localization
  12. Fermi trigger No 754701230: Global MASTER-Net observations report
  13. IPN triangulation of GRB 241128B
  14. Konus-Wind detection of GRB 241114B
  15. GRB 241128A: AbAO optical upper limit
  16. GRB 241128C: SVOM/GRM observation
  17. GRB 241128B: SVOM/GRM observation
  18. GRB 241128A: Swift-BAT refined analysis
  19. GRB 241127A: Swift-BAT refined analysis
  20. GRB 241127A: PRIME near-infrared detection
  21. GRB 241128A: Mondy optical observations
  22. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  23. Swift GRB 241128A: Global MASTER-Net observations report
  24. GRB 241128A: Swift-XRT refined Analysis
  25. GRB 241129A: Fermi GBM Final Real-time Localization
  26. GRB 241128A: Enhanced Swift-XRT position
  27. GRB 241128A: NOT optical observations
  28. GRB 241128A: LCO optical detection
  29. GRB 241128A: 1.5m OSN optical afterglow detection
  30. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  31. Fermi trigger No 754492985: Global MASTER-Net observations report
  32. GRB 241128A: Swift-XRT afterglow detection
  33. GRB 241128A: Swift detection of a burst
  34. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  35. GRB 241127A: Swift/UVOT Detection
  36. GRB 241127A: Swift-XRT refined Analysis
  37. GRB 241127A: SVOM/GRM observation
  38. GRB 241127A: Enhanced Swift-XRT position
  39. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  40. Swift GRB241127.91: Global MASTER-Net OT detection
  41. IceCube Alert 241127.59: Global MASTER-Net observations report
  42. GRB 241127A: Swift detection of a burst with an optical counterpart
  43. Swift GRB241127.91: Global MASTER-Net observations report
  44. Swift GRB241127.91: Global MASTER-Net OT detection
  45. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  46. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  47. SVOM/GRM observation of GRB 241126B or a short burst from magnetar
  48. GRB 241126A: SVOM/GRM observation
  49. IPN triangulation of GRB 241114B
  50. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  51. EP241126a: GSP detects optical counterpart
  52. EP241126a: TRT optical counterpart detection
  53. GRB 241113B: EP-FXT afterglow detection
  54. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  55. SVOM/GRM detection of a short burst from SGR 1830
  56. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  57. Konus-Wind detection of GRB 241115D / EP 241115a
  58. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  59. GRB 241026A: radio detection with the VLA
  60. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  61. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  62. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  63. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  64. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  65. GRB 241120A: GRBAlpha detection
  66. GRB 241113B: SVOM/VT optical afterglow observations
  67. Konus-Wind detection of GRB 241117A
  68. GRB 241105A: ATCA radio detection
  69. IPN triangulation of GRB 241117A
  70. GRB 241026A: VIRT Optical Upper Limit
  71. GRB 241025A: VIRT Optical Upper Limit
  72. Konus-Wind detection of GRB 241120A
  73. GRB 241120A: CALET Gamma-Ray Burst Monitor detection
  74. EP241021a and EP241026b: Keck/LRIS spectroscopic observations
  75. EP trigger ID 01709065118: Keck/LRIS spectroscopic observations
  76. EP-WXT trigger 01709018832: Lick/Kast spectroscopy with the 3 m Shane telescope
  77. GRB 241120A: Mondy and AbAO optical observations
  78. EP trigger ID 01709122294: the X-ray transient is likely a stellar flare event
  79. EP241119a: GIT optical upper limits
  80. GRB 241113A: Possible ATCA Radio detection
  81. GRB 241120A: Fermi GBM Observation
  82. GRB 241114B: Insight-HXMT/HE detection
  83. Integral GRB241120.25: Global MASTER-Net observations report
  84. EP241119a: Global MASTER-Net observations report
  85. GRB241120A: a long GRB detected by INTEGRAL
  86. GRB 241120A: Fermi GBM Final Real-time Localization
  87. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  88. GRB 241112B: Mephisto further optical observations
  89. GRB 241119A: Fermi GBM Final Real-time Localization
  90. GRB 241030A: J-band observations
  91. GRB 241115a: PRIME near-infrared upper limits
  92. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  93. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  94. GRB 241115B: Fermi GBM Observation
  95. Fermi GRB 241118A: Global MASTER-Net observations report
  96. GRB 241118A: Fermi GBM Final Real-time Localization
  97. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  98. GRB 241117A: Fermi GBM Detection
  99. Fermi GRB 241117B: Global MASTER-Net observations report
  100. GRB 241117B: Fermi GBM Final Real-time Localization

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