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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"

32509 results found.

  1. GRB 241128A : RAPAS follow-up observations
  2. GRB 241201A: GRBAlpha detection
  3. EP241202b: Upper limits from Fermi-GBM Observations
  4. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  5. EP241202b: Kinder optical counterpart candidate
  6. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  7. GRB 241113B : RAPAS follow-up observation
  8. EP241201a: EP-FXT follow-up observations
  9. Konus-Wind detection of GRB 241130A
  10. EP241202b: Global MASTER-Net observations report
  11. EP241201a: BOOTES-5 optical upper limit
  12. EP241201a: NOT optical observations
  13. IPN triangulation of GRB 241130A
  14. GRB 241130A: EIRSAT-1 GMOD Detection
  15. GRB 241128A: Swift/UVOT Upper Limits
  16. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  18. EP241201a: Kinder optical counterpart candidate
  19. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  20. EP241201a: Global MASTER-Net observations report
  21. LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
  22. EP241126a: SOAR observations of the optical counterpart
  23. Fermi GRB 241201A: Global MASTER-Net observations report
  24. EP241126a: 1.6m Mephisto Optical Upper Limits
  25. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  26. LIGO/Virgo/KAGRA S241130be: Updated Sky localization
  27. IPN triangulation of GRB 241128B
  28. Konus-Wind detection of GRB 241114B
  29. LIGO/Virgo/KAGRA S241130n: Updated Sky localization
  30. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  31. GRB 241128A: AbAO optical upper limit
  32. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  33. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  34. LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
  35. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  36. GRB 241128A: Swift-BAT refined analysis
  37. GRB 241127A: Swift-BAT refined analysis
  38. EP241126a: NOT optical observations
  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. Swift GRB 241128A: Global MASTER-Net observations report
  44. Fermi-LAT gamma-ray observations of IceCube-241127A
  45. EP241126a: SVOM/VT observations
  46. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  47. GRB 241128A: NOT optical observations
  48. GRB 241128A: LCO optical detection
  49. GRB 241128A: 1.5m OSN optical afterglow detection
  50. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  51. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  52. GRB 241127A: Swift/UVOT Detection
  53. GRB 241127A: SVOM/GRM observation
  54. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  55. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  56. EP241126a: WFST Observations
  57. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  58. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  59. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  60. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345)
  61. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345).
  62. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  63. EP241126a: Optical Upper limits with Kinder observations
  64. SVOM/GRM observation of GRB 241126B or a short burst from magnetar
  65. IPN triangulation of GRB 241114B
  66. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  67. EP241126a: EP-FXT follow-up observation update
  68. EP241126a: GSP detects optical counterpart
  69. EP241126a: TRT optical counterpart detection
  70. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  71. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  72. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  73. Trigger_18947: Swift ToO observations (retracted)
  74. GRB 241113B: EP-FXT afterglow detection
  75. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  76. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  77. SVOM/GRM 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. Konus-Wind detection of GRB 241115D / EP 241115a
  81. LIGO/Virgo/KAGRA S241125n: HCT upper limit
  82. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  83. GRB 241026A: radio detection with the VLA
  84. EP241125a: Optical upper limit with Kinder observations
  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 S241125n: Updated Sky localization and Coincidence with External Event
  93. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  94. GRB 241120A: GRBAlpha detection
  95. GRB 241113B: SVOM/VT optical afterglow observations
  96. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  97. Konus-Wind detection of GRB 241117A
  98. LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification
  99. GRB 241105A: ATCA radio detection
  100. LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate

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