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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"

8293 results found.

  1. EP240919a: NOT and Gemini optical observations
  2. EP240919a: GOTO optical upper limits
  3. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  4. LIGO/Virgo/KAGRA S240919bn: Updated Sky localization
  5. GRB 240918B: Fermi GBM Detection
  6. LIGO/Virgo/KAGRA S240917cb: Updated Sky localization and EM Bright Classification
  7. LIGO/Virgo/KAGRA S240916ar: Updated Sky localization and EM Bright Classification
  8. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  9. GRB 240916A: Fermi GBM Observation
  10. LIGO/Virgo/KAGRA S240917cb: Identification of a GW compact binary merger candidate
  11. GRB 240821A: radio observation with the VLA
  12. GRB 240916A: Swift-XRT afterglow detection
  13. LIGO/Virgo/KAGRA S240916ar: Identification of a GW compact binary merger candidate
  14. GRB 240916A: Swift ToO observations
  15. LIGO/Virgo/KAGRA S240915b: NED Galaxies in the Localization Volume
  16. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  17. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  18. LIGO/Virgo/KAGRA S240915bd: Updated Sky localization
  19. LIGO/Virgo/KAGRA S240915bd: Identification of a GW compact binary merger candidate
  20. LIGO/Virgo/KAGRA S240915b: Updated Sky localization and EM Bright Classification
  21. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  22. EP240913a/GRB 240913C: KAIT optical upper limit
  23. GRB 240914A: Swift ToO observations
  24. GRB 240911A: GOTO optical limits on Swift/XRT candidates
  25. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  26. GRB 240911A: Tiled Swift observations
  27. GRB 240912A: Swift detection of a burst with an optical counterpart
  28. GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
  29. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  30. GRB 240910A: GOTO candidate optical counterpart
  31. EP240908a: Optical afterglow confirmation
  32. GRB 240910A: Swift ToO observations
  33. GRB 240905E: SVOM/VT optical observations
  34. LIGO/Virgo/KAGRA S240910ci: NED Galaxies in the Localization Volume
  35. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  36. LIGO/Virgo/KAGRA S240910ci: Updated Sky localization and EM Bright Classification
  37. LIGO/Virgo/KAGRA S240910ci: Identification of a GW compact binary merger candidate
  38. EP240908a: Updates on the WXT detection result around the trigger time
  39. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  40. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  41. EP240908a: optical afterglow candidate
  42. GRB 240905B: GOTO optical upper limits
  43. LIGO/Virgo/KAGRA S240908dg: Updated Sky localization
  44. LIGO/Virgo/KAGRA S240908bs: Updated Sky localization
  45. LIGO/Virgo/KAGRA S240908dg: Identification of a GW compact binary merger candidate
  46. LIGO/Virgo/KAGRA S240908bs: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S240907cg: Updated Sky localization
  48. LIGO/Virgo/KAGRA S240907cg: Identification of a GW compact binary merger candidate
  49. GRB 240905E: GIT optical upper limit
  50. GRB 240905B: Swift ToO observations
  51. GRB 240905E: J-band observations with WINTER
  52. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  53. GRB 240905E: AKO Optical Upper Limit
  54. GRB 240905E: Swift detection of a burst
  55. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  56. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  57. LIGO/Virgo/KAGRA S240902bq: Updated Sky localization
  58. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  59. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  60. LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
  61. GRB 240825A: Swift-BAT refined analysis
  62. LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate
  63. GRB 240828B: SVOM/C-GFT optical upper limit
  64. GRB 240828B: KAIT optical upper limit
  65. GRB 240828A: KAIT Optical Afterglow Candidate
  66. GRB 240828A: Tiled Swift observations
  67. GRB 240825A: Upper limits from a neutrino search with IceCube
  68. GRB 240828B: Swift ToO observations
  69. GRB 240821A: PRIME near-infrared observations
  70. SVOM GRB 240821A: optical afterglow discovery
  71. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  72. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  73. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  74. GRB 240824B: KAIT optical upper limit
  75. GRB 240824B: NOT optical upper limit
  76. GRB 240825A: Skynet Optical Afterglow observations
  77. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  78. GRB 240824A: SVOM/C-GFT optical upper limit
  79. LIGO/Virgo/KAGRA S240825ar: Identification of a GW compact binary merger candidate
  80. GRB 240824B: Swift ToO observations
  81. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  82. GRB 240824A: Swift detection of a burst
  83. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  84. EP240820a: PRIME J-band Observations
  85. GRB 240821A: GMG Optical Upper Limit
  86. GRB 240821A: Swift ToO observations
  87. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  88. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  89. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  90. GRB 240819A: KAIT optical upper limit
  91. EP240816a: PRIME upper limits
  92. GRB 240819A: Swift ToO observations
  93. IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
  94. EP240816b: KAIT optical upper limit
  95. LIGO/Virgo/KAGRA S240813d: Updated Sky localization
  96. LIGO/Virgo/KAGRA S240813d: Identification of a GW compact binary merger candidate
  97. LIGO/Virgo/KAGRA S240813c: Updated Sky localization
  98. LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
  99. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  100. EP240801a: Assy-Turgen optical observations

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