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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"

32502 results found.

  1. EP241201a: EP-FXT follow-up observations
  2. Konus-Wind detection of GRB 241130A
  3. EP241202b: Global MASTER-Net observations report
  4. EP241201a: BOOTES-5 optical upper limit
  5. EP241201a: NOT optical observations
  6. IPN triangulation of GRB 241130A
  7. GRB 241130A: EIRSAT-1 GMOD Detection
  8. GRB 241128A: Swift/UVOT Upper Limits
  9. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  10. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  11. EP241201a: Kinder optical counterpart candidate
  12. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  13. EP241201a: Global MASTER-Net observations report
  14. LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
  15. EP241126a: SOAR observations of the optical counterpart
  16. Fermi GRB 241201A: Global MASTER-Net observations report
  17. EP241126a: 1.6m Mephisto Optical Upper Limits
  18. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  19. LIGO/Virgo/KAGRA S241130be: Updated Sky localization
  20. IPN triangulation of GRB 241128B
  21. Konus-Wind detection of GRB 241114B
  22. LIGO/Virgo/KAGRA S241130n: Updated Sky localization
  23. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  24. GRB 241128A: AbAO optical upper limit
  25. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  26. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  27. LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
  28. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  29. GRB 241128A: Swift-BAT refined analysis
  30. GRB 241127A: Swift-BAT refined analysis
  31. EP241126a: NOT optical observations
  32. GRB 241127A: PRIME near-infrared detection
  33. GRB 241128A: Mondy optical observations
  34. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  35. Swift-XRT observations of IceCube -241127A
  36. Swift GRB 241128A: Global MASTER-Net observations report
  37. Fermi-LAT gamma-ray observations of IceCube-241127A
  38. EP241126a: SVOM/VT observations
  39. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  40. GRB 241128A: NOT optical observations
  41. GRB 241128A: LCO optical detection
  42. GRB 241128A: 1.5m OSN optical afterglow detection
  43. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  44. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  45. GRB 241127A: Swift/UVOT Detection
  46. GRB 241127A: SVOM/GRM observation
  47. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  48. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  49. EP241126a: WFST Observations
  50. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  51. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  52. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  53. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345)
  54. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345).
  55. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  56. EP241126a: Optical Upper limits with Kinder observations
  57. SVOM/GRM observation of GRB 241126B or a short burst from magnetar
  58. IPN triangulation of GRB 241114B
  59. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  60. EP241126a: EP-FXT follow-up observation update
  61. EP241126a: GSP detects optical counterpart
  62. EP241126a: TRT optical counterpart detection
  63. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  64. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  65. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  66. Trigger_18947: Swift ToO observations (retracted)
  67. GRB 241113B: EP-FXT afterglow detection
  68. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  69. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  70. SVOM/GRM detection of a short burst from SGR 1830
  71. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  72. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  73. Konus-Wind detection of GRB 241115D / EP 241115a
  74. LIGO/Virgo/KAGRA S241125n: HCT upper limit
  75. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  76. GRB 241026A: radio detection with the VLA
  77. EP241125a: Optical upper limit with Kinder observations
  78. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  79. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  80. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  81. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  82. LIGO/Virgo/KAGRA S241125n: Updated Sky localization
  83. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  84. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  85. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  86. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  87. GRB 241120A: GRBAlpha detection
  88. GRB 241113B: SVOM/VT optical afterglow observations
  89. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  90. Konus-Wind detection of GRB 241117A
  91. LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification
  92. GRB 241105A: ATCA radio detection
  93. LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate
  94. IPN triangulation of GRB 241117A
  95. GRB 241026A: VIRT Optical Upper Limit
  96. GRB 241025A: VIRT Optical Upper Limit
  97. Konus-Wind detection of GRB 241120A
  98. GRB241120A: OHP/T193 optical observations
  99. GRB 241120A: CALET Gamma-Ray Burst Monitor detection
  100. EP241021a and EP241026b: Keck/LRIS spectroscopic observations

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