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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"

8474 results found.

  1. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
  2. LIGO/Virgo/KAGRA S240525p: Updated Sky localization
  3. LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
  4. GRB 240523A: Swift detection of a burst
  5. Fermi GBM Sub-Threshold Detection of GRB 240516B
  6. LIGO/Virgo/KAGRA S240520cv: Updated Sky localization and EM Bright Classification
  7. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  8. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  9. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  10. LIGO/Virgo/KAGRA S240520cv: Identification of a GW compact binary merger candidate
  11. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  12. LIGO/Virgo/KAGRA S240514c: Updated Sky localization
  13. GRB 240516A: Swift-BAT refined analysis
  14. GRB 240513A: Swift ToO observations
  15. GRB 240514E: A possible candidate BD-21 1074
  16. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  17. GRB 240516A: Swift detection of a burst
  18. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  19. GRB 240511A: radio detection of afterglow candidate
  20. GRB 240514B: GOTO candidate optical counterpart
  21. LIGO/Virgo/KAGRA S240514x: Updated Sky localization
  22. LIGO/Virgo/KAGRA S240515m: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo/KAGRA S240513ei: Updated Sky localization
  24. LIGO/Virgo/KAGRA S240514x: Identification of a GW compact binary merger candidate
  25. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  26. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  27. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  28. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  29. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  30. GRB 240513A: Tiled Swift observations
  31. LIGO/Virgo/KAGRA S240513ei: Identification of a GW compact binary merger candidate
  32. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  33. LIGO/Virgo/KAGRA S240512r: Updated Sky localization and EM Bright Classification
  34. LIGO/Virgo/KAGRA S240512r: Identification of a GW compact binary merger candidate
  35. GRB 240511A: Swift detection of a burst
  36. LIGO/Virgo/KAGRA S240511i: Updated Sky localization
  37. LIGO/Virgo/KAGRA S240511i: Identification of a GW compact binary merger candidate
  38. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  39. LIGO/Virgo/KAGRA S240422ed: Candidates from the latest GW-MMADS DECam Observations
  40. GRB 240504A: Fermi GBM Observation
  41. LIGO/Virgo/KAGRA S240507p: Updated Sky localization and EM Bright Classification
  42. LIGO/Virgo/KAGRA S240422ed: Upper limits from a two-week IceCube neutrino search
  43. LIGO/Virgo/KAGRA S240507p: Identification of a GW compact binary merger candidate
  44. LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
  45. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs
  46. LIGO/Virgo/KAGRA S240505av: Updated Sky localization and EM Bright Classification
  47. LIGO/Virgo/KAGRA S240505av: Identification of a GW compact binary merger candidate
  48. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  49. GRB 240502C: GOTO possible optical counterpart candidates
  50. LIGO/Virgo/KAGRA S240501an: Updated Sky localization and EM Bright Classification
  51. LIGO/Virgo/KAGRA S240430ca: Updated Sky localization and EM Bright Classification
  52. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  53. LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
  54. LIGO/Virgo/KAGRA S240430ca: Updated Sky localization and EM Bright Classification
  55. LIGO/Virgo/KAGRA S240430ca: Identification of a GW compact binary merger candidate
  56. Additional DECam GW-MMADS Candidates from three nights of observations
  57. LIGO/Virgo/KAGRA S240426s: Updated Sky localization
  58. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
  59. LIGO/Virgo/KAGRA S240426dl: Updated Sky localization
  60. LIGO/Virgo/KAGRA S240428dr: Updated Sky localization
  61. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
  62. LIGO/Virgo/KAGRA S240429an: Retraction of GW compact binary merger candidate
  63. LIGO/Virgo/KAGRA S240428dr: Identification of a GW compact binary merger candidate
  64. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of J-GEM24a
  65. LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
  66. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  67. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  68. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  69. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  70. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfq, AT2024hfr, AT2024hfs, and AT2024hfx
  71. LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
  72. LIGO/Virgo/KAGRA S240426dl: Identification of a GW compact binary merger candidate
  73. LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a
  74. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  75. EP240426a: GMG optical upper limit
  76. LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
  77. LIGO/Virgo/KAGRA S240426s: Identification of a GW compact binary merger candidate
  78. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  79. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  80. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  81. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search update and AT2024hfx, AT2024hgl observations
  82. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  83. LIGO/Virgo/KAGRA S240422ed: PRIME near-infrared observations
  84. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  85. LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
  86. LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations
  87. LIGO/Virgo/KAGRA S240422ed: ANU 2.3m followup of candidate counterparts
  88. LIGO/Virgo/KAGRA S240422ed: Magellan Spectrum of GW-MMADS Candidate AT2024hdo Indicates a Type II SN
  89. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  90. LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
  91. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  92. LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure
  93. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  94. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  95. LIGO/Virgo/KAGRA S240422ed: MOSFIRE spectroscopy of the DECam GW-MMADS candidate AT 2024hdn
  96. LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
  97. LIGO/Virgo/KAGRA S240422ed: MOSFIRE imaging of the DECam GW-MMADS candidate AT 2024hdm
  98. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  99. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of Mag24a
  100. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a

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