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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

32717 results found.

  1. LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
  2. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  3. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  4. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  5. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  6. LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations
  7. LIGO/Virgo/KAGRA S240422ed: ANU 2.3m followup of candidate counterparts
  8. LIGO/Virgo/KAGRA S240422ed: Magellan Spectrum of GW-MMADS Candidate AT2024hdo Indicates a Type II SN
  9. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  10. GRB 240419B: Swift-BAT refined analysis
  11. GRB 240421B: Swift-BAT refined analysis
  12. GRB 240422A: Glowbug gamma-ray detection
  13. LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
  14. LIGO/Virgo/KAGRA S240413p: DESGW DECam Follow-Up
  15. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  16. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  17. LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure
  18. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  19. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  20. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  21. LIGO/Virgo/KAGRA S240422ed: MOSFIRE spectroscopy of the DECam GW-MMADS candidate AT 2024hdn
  22. LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
  23. LIGO/Virgo/KAGRA S240422ed: MOSFIRE imaging of the DECam GW-MMADS candidate AT 2024hdm
  24. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  25. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of Mag24a
  26. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  27. LIGO/Virgo/KAGRA S240422ed: Archival DECaPSs2 observations of the field of Mag24a
  28. LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates
  29. LIGO/Virgo/KAGRA S240422ed: Potential Magellan candidates from GCN 36263 are unrelated.
  30. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  31. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  32. GRB 240421B: GRBAlpha detection
  33. LIGO/Virgo/KAGRA S240422ed: Magellan Detection of a Potential Electromagnetic Counterpart
  34. LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
  35. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  36. LIGO/Virgo/KAGRA S240422ed: LAST optical observations
  37. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  38. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  39. IceCube-240419A: Upper limits from a search for additional neutrino events in IceCube
  40. LIGO/Virgo/KAGRA S240421ar: Updated Sky localization
  41. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  42. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from Pan-STARRS observations of the skymap
  43. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  44. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  45. GRB 240419A: Swift-BAT refined analysis
  46. GRB 240418A: Swift-BAT refined analysis
  47. LXT240402A/GRB240402B: Chandra X-ray detection
  48. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
  49. GRB 240419A: Possible ATCA radio detection
  50. GRB 240421B: ATCA radio observations
  51. LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
  52. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  53. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  54. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam observations
  55. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  56. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  57. LIGO/Virgo/KAGRA S240422ed: Updated Sky localization and EM Bright Classification
  58. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  59. LIGO/Virgo/KAGRA S240422ed: MeerLICHT and BlackGEM observations report
  60. LIGO/Virgo/KAGRA S240422ed: Identification of a GW compact binary merger candidate
  61. GRB 240421A: Glowbug gamma-ray detection
  62. GRB 240414A: radio detection with the VLA
  63. Fermi-LAT gamma-ray observations of IceCube-240419A
  64. GRB 240414A: AMI-LA radio observations
  65. GRB 240414A: LBT optical detection
  66. GRB 240419B : MITSuME Akeno optical upper limits
  67. Fermi GRB 240422A: Global MASTER-Net observations report
  68. GRB 240421B: AstroSat CZTI detection
  69. Fermi GRB 240421B: Global MASTER-Net observations report
  70. Swift GRB 240421B: Global MASTER-Net observations report
  71. GRB 240421B: Fermi GBM Observation
  72. GRB 240421B: J-band upper limits from WINTER
  73. GRB 240421B: Swift/UVOT Upper Limits
  74. Fermi GRB 240421A: Global MASTER-Net observations report
  75. EP240417a: no counterpart detection by SOAR
  76. EP240420a: TNT upper limit to its optical counterpart
  77. EP240420a: Nanshan optical counterpart observations
  78. EP240420a: GWAC-F50A optical upper limit
  79. LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
  80. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  81. EP240420a: NOT optical counterpart candidate and potential host
  82. GRB240419A: Skynet Optical Afterglow Analysis
  83. GRB240418A - Candidate afterglow from NIRES
  84. GRB 240419B: Swift/UVOT Upper Limits
  85. GRB 240419A: Swift/UVOT Upper Limits
  86. GRB 240419B: optical afterglow from the NOT
  87. EP240414a: Near-IR observations with NIRES and WINTER
  88. Swift GRB 240419B: Global MASTER-Net observations report
  89. EP240414A: Terskol Zeiss-2000 optical upper limit
  90. Swift GRB 240419A: Global MASTER-Net observations report
  91. GRB 240418A: Swift/UVOT Upper Limits
  92. GRB 240419A: REM NIR afterglow detection
  93. GRB 240411B: Swift/UVOT Detection
  94. EP240417a: YAHPT Optical Upper Limits
  95. GRB240418A: YAHPT Upper Limits
  96. GRB 240419A: VLT/UVES redshift of z = 5.178
  97. GRB 240419A: VLT optical afterglow detection
  98. EP240416a: J-band observations with WINTER
  99. EP240414a: GMG observation
  100. GRB 240418A: TSHAO Zeiss-1000 optical upper limit

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