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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"

21089 results found.

  1. Fermi GRB 240501A: Global MASTER-Net observations report
  2. Fermi trigger No 736197684: Global MASTER-Net observations report
  3. MeerKAT Discovery of a Probable Radio Counterpart to EP240414a
  4. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  5. Additional DECam GW-MMADS Candidates from three nights of observations
  6. Fermi-LAT gamma-ray observations of IceCube-240424A
  7. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
  8. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
  9. LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a
  10. Fermi GRB 240428A: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of J-GEM24a
  12. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  13. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  14. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  15. EP240426b: EP-WXT detection of a new fast X-ray transient
  16. LIGO/Virgo/KAGRA S240422ed: Archival radio detection of EP240426a
  17. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfq, AT2024hfr, AT2024hfs, and AT2024hfx
  18. LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
  19. GRB 240414A: NOEMA detection
  20. LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
  21. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  22. LVK S240422ed: Further Swift-XRT followup of three sources
  23. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  24. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  25. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search update and AT2024hfx, AT2024hgl observations
  26. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  27. LIGO/Virgo/KAGRA S240422ed: PRIME near-infrared observations
  28. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  29. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  30. LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
  31. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  32. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  33. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  34. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  35. LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations
  36. LIGO/Virgo/KAGRA S240422ed: ANU 2.3m followup of candidate counterparts
  37. LIGO/Virgo/KAGRA S240422ed: Magellan Spectrum of GW-MMADS Candidate AT2024hdo Indicates a Type II SN
  38. Fermi trigger No 735697285: Global MASTER-Net observations report
  39. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  40. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  41. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  42. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  43. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  44. LIGO/Virgo/KAGRA S240422ed: MOSFIRE spectroscopy of the DECam GW-MMADS candidate AT 2024hdn
  45. LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
  46. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  47. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  48. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  49. LIGO/Virgo/KAGRA S240422ed: Archival DECaPSs2 observations of the field of Mag24a
  50. LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates
  51. LIGO/Virgo/KAGRA S240422ed: Potential Magellan candidates from GCN 36263 are unrelated.
  52. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  53. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  54. IceCube Alert 240424.08: Global MASTER-Net observations report
  55. LIGO/Virgo/KAGRA S240422ed: Magellan Detection of a Potential Electromagnetic Counterpart
  56. LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
  57. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  58. LIGO/Virgo/KAGRA S240422ed: LAST optical observations
  59. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  60. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  61. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from Pan-STARRS observations of the skymap
  62. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  63. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  64. LXT240402A/GRB240402B: Chandra X-ray detection
  65. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
  66. GRB 240419A: Possible ATCA radio detection
  67. GRB 240421B: ATCA radio observations
  68. LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
  69. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  70. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam observations
  71. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  72. LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
  73. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  74. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  75. LIGO/Virgo/KAGRA S240422ed: MeerLICHT and BlackGEM observations report
  76. LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
  77. LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
  78. Fermi trigger No 735470374: Global MASTER-Net observations report
  79. GRB 240414A: radio detection with the VLA
  80. Fermi-LAT gamma-ray observations of IceCube-240419A
  81. GRB 240414A: AMI-LA radio observations
  82. GRB 240414A: LBT optical detection
  83. GRB 240415B: Swift-XRT observations
  84. Fermi GRB 240422A: Global MASTER-Net observations report
  85. GRB240421B: Zadko Observations
  86. Fermi GRB 240421B: Global MASTER-Net observations report
  87. Swift GRB 240421B: Global MASTER-Net observations report
  88. GRB 240421B: J-band upper limits from WINTER
  89. GRB 240421B: Swift/UVOT Upper Limits
  90. Fermi GRB 240421A: Global MASTER-Net observations report
  91. EP240420a: TNT upper limit to its optical counterpart
  92. EP240420a: Xinglong decaying optical counterpart
  93. EP240420a: Nanshan optical counterpart observations
  94. EP240420a: NOT optical counterpart candidate and potential host
  95. Fermi trigger No 735280430: Global MASTER-Net observations report
  96. GRB240418A - Candidate afterglow from NIRES
  97. IceCube Alert 240419.98: Global MASTER-Net observations report
  98. GRB 240419B: Swift/UVOT Upper Limits
  99. GRB 240419A: Swift/UVOT Upper Limits
  100. GRB 240419B: optical afterglow from the NOT

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