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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

24608 results found.

  1. Fermi GRB 241207B: Global MASTER-Net observations report
  2. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  3. GRB 241206A: DDOTI Upper Limit on the Afterglow
  4. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  5. GRB 241207C: MAXI/GSC detection
  6. EP241206a: EP detection of a fast X-ray transient
  7. GRB 241206A: Fermi GBM observation
  8. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  9. EP241201a: 1.6m Mephisto Optical Upper Limits
  10. GRB 241204A: COLIBRÍ Optical Upper Limit
  11. EP241202b: KAIT optical upper limit
  12. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  13. GRB 241204A: DDOTI Upper Limits on the Afterglow
  14. GRB 241130A: CALET Gamma-Ray Burst Monitor detection
  15. GRB 241128A : RAPAS follow-up observations
  16. EP241202b: Upper limits from Fermi-GBM Observations
  17. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  18. EP241202b: Kinder optical counterpart candidate
  19. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  20. GRB 241113B : RAPAS follow-up observation
  21. Konus-Wind detection of GRB 241130A
  22. EP241201a: BOOTES-5 optical upper limit
  23. EP241202b: EP detection of a fast X-ray transient
  24. EP241201a: NOT optical observations
  25. IPN triangulation of GRB 241130A
  26. GRB 241130A: EIRSAT-1 GMOD Detection
  27. GRB 241128A: Swift/UVOT Upper Limits
  28. GRB 241130A: Fermi GBM Detection
  29. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  30. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  31. EP241201a: Kinder optical counterpart candidate
  32. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  33. LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
  34. GRB 241201A: BALROG localization (Fermi Trigger 754757764 / GRB 241201622)
  35. EP241126a: 1.6m Mephisto Optical Upper Limits
  36. GRB 241201A: Fermi GBM Final Real-time Localization
  37. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  38. LIGO/Virgo/KAGRA S241130be: Updated Sky localization
  39. Fermi trigger No 754701230: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S241130n: Updated Sky localization
  41. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  42. GRB 241128A: AbAO optical upper limit
  43. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  44. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  45. LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
  46. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  47. GRB 241128A: Swift-BAT refined analysis
  48. GRB 241127A: Swift-BAT refined analysis
  49. GRB 241127A: PRIME near-infrared detection
  50. GRB 241128A: Mondy optical observations
  51. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  52. Swift-XRT observations of IceCube -241127A
  53. Fermi-LAT gamma-ray observations of IceCube-241127A
  54. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  55. GRB 241128A: Swift-XRT refined Analysis
  56. GRB 241128A: Enhanced Swift-XRT position
  57. GRB 241128A: NOT optical observations
  58. GRB 241128A: LCO optical detection
  59. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  60. GRB 241128A: Swift-XRT afterglow detection
  61. GRB 241128A: Swift detection of a burst
  62. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  63. GRB 241127A: Swift/UVOT Detection
  64. GRB 241127A: Swift-XRT refined Analysis
  65. GRB 241127A: Enhanced Swift-XRT position
  66. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  67. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  68. Swift GRB241127.91: Global MASTER-Net OT detection
  69. EP241126a: WFST Observations
  70. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  71. GRB 241127A: Swift detection of a burst with an optical counterpart
  72. Swift GRB241127.91: Global MASTER-Net OT detection
  73. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  74. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  75. LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
  76. EP241126a: Optical Upper limits with Kinder observations
  77. IPN triangulation of GRB 241114B
  78. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  79. EP241126a: GSP detects optical counterpart
  80. EP241126a: TRT optical counterpart detection
  81. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  82. EP241126a: EP detection of a fast X-ray transient
  83. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  84. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  85. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  86. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  87. GECAM detection of a short burst from SGR 1830
  88. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  89. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  90. LIGO/Virgo/KAGRA S241125n: HCT upper limit
  91. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  92. GRB 241026A: radio detection with the VLA
  93. EP241125a: Optical upper limit with Kinder observations
  94. EP241125a: EP detection of an X-ray transient
  95. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  96. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  97. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  98. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  99. LIGO/Virgo/KAGRA S241125n: Updated Sky localization
  100. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event

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