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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"

24705 results found.

  1. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  2. GRB 241207C: MAXI/GSC detection
  3. EP241206a: EP detection of a fast X-ray transient
  4. GRB 241206A: Fermi GBM observation
  5. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  6. EP241201a: 1.6m Mephisto Optical Upper Limits
  7. GRB 241204A: COLIBRÍ Optical Upper Limit
  8. EP241202b: KAIT optical upper limit
  9. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  10. GRB 241204A: DDOTI Upper Limits on the Afterglow
  11. GRB 241130A: CALET Gamma-Ray Burst Monitor detection
  12. GRB 241128A : RAPAS follow-up observations
  13. EP241202b: Upper limits from Fermi-GBM Observations
  14. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  15. EP241202b: Kinder optical counterpart candidate
  16. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  17. GRB 241113B : RAPAS follow-up observation
  18. Konus-Wind detection of GRB 241130A
  19. EP241201a: BOOTES-5 optical upper limit
  20. EP241202b: EP detection of a fast X-ray transient
  21. EP241201a: NOT optical observations
  22. IPN triangulation of GRB 241130A
  23. GRB 241130A: EIRSAT-1 GMOD Detection
  24. GRB 241128A: Swift/UVOT Upper Limits
  25. GRB 241130A: Fermi GBM Detection
  26. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  27. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  28. EP241201a: Kinder optical counterpart candidate
  29. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  30. LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
  31. GRB 241201A: BALROG localization (Fermi Trigger 754757764 / GRB 241201622)
  32. EP241126a: 1.6m Mephisto Optical Upper Limits
  33. GRB 241201A: Fermi GBM Final Real-time Localization
  34. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S241130be: Updated Sky localization
  36. Fermi trigger No 754701230: Global MASTER-Net observations report
  37. LIGO/Virgo/KAGRA S241130n: Updated Sky localization
  38. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  39. GRB 241128A: AbAO optical upper limit
  40. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  41. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  42. LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
  43. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  44. GRB 241128A: Swift-BAT refined analysis
  45. GRB 241127A: Swift-BAT refined analysis
  46. GRB 241127A: PRIME near-infrared detection
  47. GRB 241128A: Mondy optical observations
  48. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  49. Swift-XRT observations of IceCube -241127A
  50. Fermi-LAT gamma-ray observations of IceCube-241127A
  51. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  52. GRB 241128A: Swift-XRT refined Analysis
  53. GRB 241128A: Enhanced Swift-XRT position
  54. GRB 241128A: NOT optical observations
  55. GRB 241128A: LCO optical detection
  56. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  57. GRB 241128A: Swift-XRT afterglow detection
  58. GRB 241128A: Swift detection of a burst
  59. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  60. GRB 241127A: Swift/UVOT Detection
  61. GRB 241127A: Swift-XRT refined Analysis
  62. GRB 241127A: Enhanced Swift-XRT position
  63. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  64. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  65. Swift GRB241127.91: Global MASTER-Net OT detection
  66. EP241126a: WFST Observations
  67. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  68. GRB 241127A: Swift detection of a burst with an optical counterpart
  69. Swift GRB241127.91: Global MASTER-Net OT detection
  70. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  71. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  72. LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
  73. EP241126a: Optical Upper limits with Kinder observations
  74. IPN triangulation of GRB 241114B
  75. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  76. EP241126a: GSP detects optical counterpart
  77. EP241126a: TRT optical counterpart detection
  78. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  79. EP241126a: EP detection of a fast X-ray transient
  80. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  81. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  82. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  83. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  84. GECAM detection of a short burst from SGR 1830
  85. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  86. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  87. LIGO/Virgo/KAGRA S241125n: HCT upper limit
  88. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  89. GRB 241026A: radio detection with the VLA
  90. EP241125a: Optical upper limit with Kinder observations
  91. EP241125a: EP detection of an X-ray transient
  92. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  93. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  94. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  95. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  96. LIGO/Virgo/KAGRA S241125n: Updated Sky localization
  97. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  98. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  99. LIGO/Virgo/KAGRA S241109bn: Upper limits from a two-week IceCube neutrino search
  100. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event

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