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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"

24608 results found.

  1. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  2. LIGO/Virgo/KAGRA S241109bn: Upper limits from a two-week IceCube neutrino search
  3. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  4. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  5. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  6. LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification
  7. LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate
  8. IPN triangulation of GRB 241117A
  9. GRB 241026A: VIRT Optical Upper Limit
  10. GRB 241025A: VIRT Optical Upper Limit
  11. GRB241120A: OHP/T193 optical observations
  12. EP241021a and EP241026b: Keck/LRIS spectroscopic observations
  13. GRB 241120A: Mondy and AbAO optical observations
  14. EP241119a: Optical upper limits with Kinder observations
  15. EP trigger ID 01709122294: the X-ray transient is likely a stellar flare event
  16. EP241119a: GIT optical upper limits
  17. EP241119a : J-band observations with WINTER
  18. GRB 241120A: Fermi GBM Observation
  19. EP241119a: EP detection of a fast X-ray transient
  20. GRB241120A: a long GRB detected by INTEGRAL
  21. GRB 241112B: Mephisto further optical observations
  22. GRB 241030A: J-band observations
  23. GRB 241115a: PRIME near-infrared upper limits
  24. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  25. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  26. GRB 241115B: Fermi GBM Observation
  27. LIGO/Virgo/KAGRA S241114y: Updated Sky localization
  28. Updates to IceCube realtime alert system for muon tracks
  29. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  30. GRB 241117A: Fermi GBM Detection
  31. IceCube-Cascade 241116A: Upper limits from a search for additional neutrino events in IceCube
  32. LIGO/Virgo/KAGRA S241116cq: Updated Sky localization
  33. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  34. GRB 241115C: Fermi GBM Observation
  35. GRB 241115A: Swift-XRT afterglow detection
  36. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  37. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  38. GRB 241115A: Mephisto upper limits
  39. GRB 241113B: Mephisto upper limits
  40. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  41. GRB 241115D / EP 241115a: SVOM/GRM observation
  42. EP241113a: Swift XRT weak detection
  43. GRB 241115A: Fermi GBM Observation
  44. GRB 241115A: LCOGT Optical Upper Limits
  45. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  46. LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
  47. LIGO/Virgo/KAGRA S241113p: Updated Sky localization
  48. EP241115a: EP detection of a fast X-ray transient
  49. Swift GRB 241115A: Global MASTER-Net observations report
  50. Fermi GRB 241115A: Global MASTER-Net observations report
  51. GRB 241115A: Swift detection of a burst
  52. EP 241113a: LBT possible optical counterpart
  53. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  54. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  55. GRB 241113A: Swift-BAT refined analysis
  56. LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
  57. GRB 241113A: PRIME near-infrared upper limits
  58. EP241113a: Global MASTER-Net observations report
  59. GRB 241113B: J-band upper limit from WINTER
  60. GRB 241113A: J-band observations with WINTER
  61. EP241113a : J-band observations with WINTER
  62. GRB 241030A: LCO optical observation
  63. GRB 241113B: Swift-XRT observations
  64. IceCube-241113A: Upper limits from a search for additional neutrino events in IceCube
  65. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  66. EP241113b/GRB 241113B: EP detection of GRB 241113B
  67. Fermi-LAT gamma-ray observations of IceCube-241113A
  68. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  69. GRB 241113A: Swift-XRT refined Analysis
  70. GRB 241113A: Swift/UVOT Detection
  71. GRB 241113A: REM detection of the optical/NIR afterglow
  72. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  73. GRB 241113A: LCO optical observations
  74. GRB 241112B: GMG Optical Upper Limit
  75. GRB 241113A: Enhanced Swift-XRT position
  76. GRB241113A: LCOGT (40-cm) optical counterpart detection
  77. GRB 241113A: Swift detection of a burst with an optical counterpart
  78. SVOM/GRM detection of a short burst from SGR 1E1841-045
  79. LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
  80. GRB 241112B: AbAO optical upper limit
  81. GRB 241107A: GROWTH-India telescope optical upper limit
  82. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  83. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  84. GRB 241112B: Swift-XRT afterglow detection
  85. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  86. GRB 241112B: Mephisto optical upper limits
  87. GRB 241112B: GOTO optical upper limits
  88. GRB 241107A: INTEGRAL IBIS localization
  89. LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
  90. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  91. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  92. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  93. IPN triangulation of GRB 241107A (short/hard)
  94. GRB 241025C: VZLUSAT-2 detection
  95. GRB 241025A: VZLUSAT-2 detection
  96. GRB 241018A: cubesat Avion detection
  97. GRB 241030B: TESS detection of optical counterpart
  98. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  99. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  100. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate

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