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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').
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"

21983 results found.

  1. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  2. LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure
  3. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  4. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  5. LIGO/Virgo/KAGRA S240422ed: MOSFIRE spectroscopy of the DECam GW-MMADS candidate AT 2024hdn
  6. LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
  7. LIGO/Virgo/KAGRA S240422ed: MOSFIRE imaging of the DECam GW-MMADS candidate AT 2024hdm
  8. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  9. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  10. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  11. LIGO/Virgo/KAGRA S240422ed: Archival DECaPSs2 observations of the field of Mag24a
  12. LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates
  13. LIGO/Virgo/KAGRA S240422ed: Potential Magellan candidates from GCN 36263 are unrelated.
  14. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  15. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  16. IceCube Alert 240424.08: Global MASTER-Net observations report
  17. LIGO/Virgo/KAGRA S240422ed: Magellan Detection of a Potential Electromagnetic Counterpart
  18. LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
  19. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  20. LIGO/Virgo/KAGRA S240422ed: LAST optical observations
  21. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  22. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  23. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from Pan-STARRS observations of the skymap
  24. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  25. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  26. LXT240402A/GRB240402B: Chandra X-ray detection
  27. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
  28. GRB 240419A: Possible ATCA radio detection
  29. GRB 240421B: ATCA radio observations
  30. LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
  31. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  32. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam observations
  33. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  34. LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
  35. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  36. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  37. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  38. LIGO/Virgo/KAGRA S240422ed: MeerLICHT and BlackGEM observations report
  39. LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
  40. LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
  41. Fermi trigger No 735470374: Global MASTER-Net observations report
  42. GRB 240414A: radio detection with the VLA
  43. Fermi-LAT gamma-ray observations of IceCube-240419A
  44. GRB 240414A: AMI-LA radio observations
  45. GRB 240414A: LBT optical detection
  46. GRB 240415B: Swift-XRT observations
  47. Fermi GRB 240422A: Global MASTER-Net observations report
  48. GRB240421B: Zadko Observations
  49. Fermi GRB 240421B: Global MASTER-Net observations report
  50. Swift GRB 240421B: Global MASTER-Net observations report
  51. GRB 240421B: J-band upper limits from WINTER
  52. GRB 240421B: Swift/UVOT Upper Limits
  53. Fermi GRB 240421A: Global MASTER-Net observations report
  54. EP240420a: TNT upper limit to its optical counterpart
  55. EP240420a: Xinglong decaying optical counterpart
  56. EP240420a: Nanshan optical counterpart observations
  57. EP240420a: NOT optical counterpart candidate and potential host
  58. Fermi trigger No 735280430: Global MASTER-Net observations report
  59. GRB240418A - Candidate afterglow from NIRES
  60. IceCube Alert 240419.98: Global MASTER-Net observations report
  61. GRB 240419B: Swift/UVOT Upper Limits
  62. GRB 240419A: Swift/UVOT Upper Limits
  63. GRB 240419B: optical afterglow from the NOT
  64. EP240414a: Near-IR observations with NIRES and WINTER
  65. Swift GRB 240419B: Global MASTER-Net observations report
  66. Swift GRB 240419A: Global MASTER-Net observations report
  67. GRB 240418A: Swift/UVOT Upper Limits
  68. GRB 240419A: REM NIR afterglow detection
  69. GRB 240411B: Swift/UVOT Detection
  70. GRB 240419A: VLT/UVES redshift of z = 5.178
  71. GRB 240419A: VLT optical afterglow detection
  72. Fermi trigger No 735089036: Global MASTER-Net observations report
  73. EP240416a: J-band observations with WINTER
  74. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  75. GRB 240418A: NOT optical upper limits
  76. GRB 240411A: GOTO early optical upper limits
  77. Swift GRB240418.85: Global MASTER-Net observations report
  78. EP240417a: EP-WXT detection of a fast X-ray transient
  79. Fermi GRB 240417A: Global MASTER-Net observations report
  80. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  81. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  82. LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates
  83. EP240414a: Pan-STARRS detects re-brightening of the candidate counterpart AT2024gsa
  84. LIGO/Virgo/KAGRA S240413p: historical ATLAS and ZTF observations of the candidate AGN counterpart
  85. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  86. EP240416A: MASTER optical observations
  87. EP240416a: Kinder optical counterpart candidate
  88. EP240416a: EP-WXT detection of a fast X-ray transient
  89. GRB 240414A: AbAO optical upprer limit
  90. GRB 240415A: Swift/UVOT Detection
  91. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  92. GRB 240415A: Earliest optical followup with the Kinder observations
  93. GRB 240415B: Swift ToO observations
  94. GRB 240415B: Swift/BAT-GUANO Correction
  95. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  96. GRB 240415A: OHP/T193 optical observations
  97. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  98. GRB 240415A: SAO RAS optical observations
  99. Fermi GRB 240415A: Global MASTER-Net observations report
  100. GRB 240415A: Mondy optical transient detection

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