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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"

24700 results found.

  1. EP241202b: KAIT optical upper limit
  2. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  3. GRB 241204A: DDOTI Upper Limits on the Afterglow
  4. GRB 241130A: CALET Gamma-Ray Burst Monitor detection
  5. GRB 241128A : RAPAS follow-up observations
  6. EP241202b: Upper limits from Fermi-GBM Observations
  7. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  8. EP241202b: Kinder optical counterpart candidate
  9. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  10. GRB 241113B : RAPAS follow-up observation
  11. Konus-Wind detection of GRB 241130A
  12. EP241201a: BOOTES-5 optical upper limit
  13. EP241202b: EP detection of a fast X-ray transient
  14. EP241201a: NOT optical observations
  15. IPN triangulation of GRB 241130A
  16. GRB 241130A: EIRSAT-1 GMOD Detection
  17. GRB 241128A: Swift/UVOT Upper Limits
  18. GRB 241130A: Fermi GBM Detection
  19. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  20. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  21. EP241201a: Kinder optical counterpart candidate
  22. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  23. LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
  24. GRB 241201A: BALROG localization (Fermi Trigger 754757764 / GRB 241201622)
  25. EP241126a: 1.6m Mephisto Optical Upper Limits
  26. GRB 241201A: Fermi GBM Final Real-time Localization
  27. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  28. LIGO/Virgo/KAGRA S241130be: Updated Sky localization
  29. Fermi trigger No 754701230: Global MASTER-Net observations report
  30. LIGO/Virgo/KAGRA S241130n: Updated Sky localization
  31. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  32. GRB 241128A: AbAO optical upper limit
  33. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  34. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
  36. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  37. GRB 241128A: Swift-BAT refined analysis
  38. GRB 241127A: Swift-BAT refined analysis
  39. GRB 241127A: PRIME near-infrared detection
  40. GRB 241128A: Mondy optical observations
  41. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  42. Swift-XRT observations of IceCube -241127A
  43. Fermi-LAT gamma-ray observations of IceCube-241127A
  44. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  45. GRB 241128A: Swift-XRT refined Analysis
  46. GRB 241128A: Enhanced Swift-XRT position
  47. GRB 241128A: NOT optical observations
  48. GRB 241128A: LCO optical detection
  49. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  50. GRB 241128A: Swift-XRT afterglow detection
  51. GRB 241128A: Swift detection of a burst
  52. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  53. GRB 241127A: Swift/UVOT Detection
  54. GRB 241127A: Swift-XRT refined Analysis
  55. GRB 241127A: Enhanced Swift-XRT position
  56. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  57. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  58. Swift GRB241127.91: Global MASTER-Net OT detection
  59. EP241126a: WFST Observations
  60. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  61. GRB 241127A: Swift detection of a burst with an optical counterpart
  62. Swift GRB241127.91: Global MASTER-Net OT detection
  63. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  64. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  65. LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
  66. EP241126a: Optical Upper limits with Kinder observations
  67. IPN triangulation of GRB 241114B
  68. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  69. EP241126a: GSP detects optical counterpart
  70. EP241126a: TRT optical counterpart detection
  71. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  72. EP241126a: EP detection of a fast X-ray transient
  73. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  74. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  75. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  76. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  77. GECAM detection of a short burst from SGR 1830
  78. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  79. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  80. LIGO/Virgo/KAGRA S241125n: HCT upper limit
  81. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  82. GRB 241026A: radio detection with the VLA
  83. EP241125a: Optical upper limit with Kinder observations
  84. EP241125a: EP detection of an X-ray transient
  85. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  86. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  87. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  88. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  89. LIGO/Virgo/KAGRA S241125n: Updated Sky localization
  90. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  91. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  92. LIGO/Virgo/KAGRA S241109bn: Upper limits from a two-week IceCube neutrino search
  93. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  94. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  95. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  96. LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification
  97. LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate
  98. IPN triangulation of GRB 241117A
  99. GRB 241026A: VIRT Optical Upper Limit
  100. GRB 241025A: VIRT Optical Upper Limit

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