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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').
Advanced Search

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"

31744 results found.

  1. IPN triangulation of GRB 241114B
  2. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  3. EP241126a: EP-FXT follow-up observation update
  4. EP241126a: GSP detects optical counterpart
  5. EP241126a: TRT optical counterpart detection
  6. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  7. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  8. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  9. Trigger_18947: Swift ToO observations (retracted)
  10. GRB 241113B: EP-FXT afterglow detection
  11. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  12. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  13. SVOM/GRM detection of a short burst from SGR 1830
  14. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  15. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  16. Konus-Wind detection of GRB 241115D / EP 241115a
  17. LIGO/Virgo/KAGRA S241125n: HCT upper limit
  18. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  19. GRB 241026A: radio detection with the VLA
  20. EP241125a: Optical upper limit with Kinder observations
  21. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  22. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  23. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  24. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  25. LIGO/Virgo/KAGRA S241125n: Updated Sky localization
  26. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  27. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  28. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  29. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  30. GRB 241120A: GRBAlpha detection
  31. GRB 241113B: SVOM/VT optical afterglow observations
  32. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  33. Konus-Wind detection of GRB 241117A
  34. LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification
  35. GRB 241105A: ATCA radio detection
  36. LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate
  37. IPN triangulation of GRB 241117A
  38. GRB 241026A: VIRT Optical Upper Limit
  39. GRB 241025A: VIRT Optical Upper Limit
  40. Konus-Wind detection of GRB 241120A
  41. GRB241120A: OHP/T193 optical observations
  42. GRB 241120A: CALET Gamma-Ray Burst Monitor detection
  43. EP241021a and EP241026b: Keck/LRIS spectroscopic observations
  44. EP trigger ID 01709065118: Keck/LRIS spectroscopic observations
  45. EP-WXT trigger 01709018832: Lick/Kast spectroscopy with the 3 m Shane telescope
  46. GRB 241120A: Mondy and AbAO optical observations
  47. EP241119a: Optical upper limits with Kinder observations
  48. EP241119a: GIT optical upper limits
  49. GRB 241113A: Possible ATCA Radio detection
  50. EP241119a : J-band observations with WINTER
  51. GRB 241120A: Fermi GBM Observation
  52. EP241119a: Global MASTER-Net observations report
  53. GRB241120A: a long GRB detected by INTEGRAL
  54. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  55. GRB 241112B: Mephisto further optical observations
  56. GRB 241030A: J-band observations
  57. GRB 241115a: PRIME near-infrared upper limits
  58. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  59. GRB 241115B: Fermi GBM Observation
  60. LIGO/Virgo/KAGRA S241114y: Updated Sky localization
  61. Fermi GRB 241118A: Global MASTER-Net observations report
  62. Updates to IceCube realtime alert system for muon tracks
  63. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  64. Fermi GRB 241117B: Global MASTER-Net observations report
  65. LIGO/Virgo/KAGRA S241116cq: Updated Sky localization
  66. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  67. Fermi GRB 241117A: Global MASTER-Net observations report
  68. GRB 241115C: Fermi GBM Observation
  69. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  70. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  71. GRB 241115A: Mephisto upper limits
  72. GRB 241113B: Mephisto upper limits
  73. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  74. GRB 241115D / EP 241115a: SVOM/GRM observation
  75. The EP-WXT trigger 01709120856 is likely a flaring star
  76. EP241113a: Swift XRT weak detection
  77. GRB 241115A: Fermi GBM Observation
  78. GRB 241115A: LCOGT Optical Upper Limits
  79. Fermi GRB 241115B: Global MASTER-Net observations report
  80. LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
  81. EP241115a: Global MASTER-Net observations report
  82. LIGO/Virgo/KAGRA S241113p: Updated Sky localization
  83. EP241113a: No Detection in Fermi-GBM Observations
  84. Swift GRB 241115A: Global MASTER-Net observations report
  85. Fermi GRB 241115A: Global MASTER-Net observations report
  86. EP 241113a: LBT possible optical counterpart
  87. GRB 241113B: KAIT Optical Afterglow Candidate
  88. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  89. GRB 241113A: Swift-BAT refined analysis
  90. LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
  91. GRB 241113A: PRIME near-infrared upper limits
  92. Fermi GRB 241114A: Global MASTER-Net observations report
  93. EP241113a: Global MASTER-Net observations report
  94. GRB 241113B: J-band upper limit from WINTER
  95. GRB 241113A: J-band observations with WINTER
  96. EP241113a : J-band observations with WINTER
  97. GRB 241030A: LCO optical observation
  98. IceCube-241113A: Upper limits from a search for additional neutrino events in IceCube
  99. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  100. GRB 241113A: KAIT optical observations

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