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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"

16146 results found.

  1. GRB 240615A: FLWO-1.2m optical upper limits
  2. GRB 240615A: GOTO optical upper limits
  3. GRB 240529A: LBT optical detection and late temporal decay
  4. GRB 240529A : MITSuME Akeno optical afterglow detection
  5. GRB 240529A: SAO RAS optical observations
  6. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  7. GRB 240529A: MASTER prompt OT detection
  8. GRB 240529A: continued SAO RAS optical observations
  9. GRB 240529A: OSN optical detection
  10. GRB 240529A: further SAO RAS optical observations
  11. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  12. LXT 240528A: GSP optical upper limit
  13. GRB 240529A: 1.3m DFOT Optical observations
  14. GRB 240529A : Mondy optical observations
  15. GRB 240529A: SAO RAS optical observations
  16. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  17. GRB 240529A: optical photometry from Konkoly
  18. GRB 240529A: GROWTH-India optical follow-up
  19. GRB 240529A: AKO Optical Afterglow Detection
  20. GRB 240529A: Skynet Optical Observations
  21. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  22. GRB240529A: BOOTES-6/DPRT optical detection
  23. GRB 240529A: NOT optical observations
  24. GRB 240529A: GOTO optical afterglow detection
  25. GRB 240529A: Swift detection of a burst with an optical counterpart
  26. EP240518a: GSP optical upper limit
  27. GRB 240516A: Swift/UVOT Upper Limits
  28. IPN triangulation of GRB 240514B (short)
  29. GRB 240514E: A possible candidate BD-21 1074
  30. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  31. GRB 240516A: GOTO optical upper limit
  32. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  33. GRB 240514B: GOTO candidate optical counterpart
  34. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  35. GRB 240511A: J-band observations with WINTER
  36. GRB 240511A : MITSuME Akeno optical upper limits
  37. GRB 240511A: optical afterglow detection from the NOT
  38. EP240506a: Xinglong optical upper limit
  39. EP240506a: CrAO ZTSH optical upper limit
  40. EP240506a: Archival radio searching
  41. EP240506a: TRT optical upper limit
  42. EP240506a: BOOTES Network optical upper limit
  43. EP240506a: Optical upper limit with Kinder observations
  44. GRB 240502A: 1.3m DFOT Optical upper limit
  45. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs
  46. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  47. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  48. GRB 240502A: GOTO optical upper limit
  49. GRB 240415A 1.3m DFOT Optical upper limit
  50. GRB 240502C: GOTO possible optical counterpart candidates
  51. X-ray transient EP240414a: Detection of associated supernova
  52. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  53. LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
  54. EP240426b: AST3-2 optical upper limit
  55. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  56. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  57. LIGO/Virgo/KAGRA S240422ed: Archival radio detection of EP240426a
  58. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfq, AT2024hfr, AT2024hfs, and AT2024hfx
  59. LIGO/Virgo/KAGRA S240422ed: BOOTES-6/DPRT optical upper limits for EP240426a
  60. LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
  61. LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a
  62. EP240426a: YAHPT optical upper limit
  63. LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a
  64. LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
  65. LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
  66. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  67. EP240426a: GMG optical upper limit
  68. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  69. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search update and AT2024hfx, AT2024hgl observations
  70. LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
  71. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  72. LIGO/Virgo/KAGRA S240422ed: ANU 2.3m followup of candidate counterparts
  73. LIGO/Virgo/KAGRA S240422ed: Magellan Spectrum of GW-MMADS Candidate AT2024hdo Indicates a Type II SN
  74. LIGO/Virgo/KAGRA S240413p: DESGW DECam Follow-Up
  75. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  76. LIGO/Virgo/KAGRA S240422ed: MOSFIRE spectroscopy of the DECam GW-MMADS candidate AT 2024hdn
  77. LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
  78. LIGO/Virgo/KAGRA S240422ed: MOSFIRE imaging of the DECam GW-MMADS candidate AT 2024hdm
  79. LIGO/Virgo/KAGRA S240422ed: J-band non-detection of Mag24a
  80. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  81. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  82. LIGO/Virgo/KAGRA S240422ed: Magellan Detection of a Potential Electromagnetic Counterpart
  83. LIGO/Virgo/KAGRA S240422ed: LAST optical observations
  84. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  85. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  86. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  87. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  88. LXT240402A/GRB240402B: Chandra X-ray detection
  89. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
  90. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  91. GRB 240414A: LBT optical detection
  92. GRB 240419B : MITSuME Akeno optical upper limits
  93. GRB240421B: BOOTES-5/JGT optical upper limit
  94. GRB 240421B: Swift/UVOT Upper Limits
  95. EP240417a: no counterpart detection by SOAR
  96. EP240420a: TNT upper limit to its optical counterpart
  97. EP240420a: Xinglong decaying optical counterpart
  98. EP240420a: Nanshan optical counterpart observations
  99. EP240420a: GWAC-F50A optical upper limit
  100. EP240420a: NOT optical counterpart candidate and potential host

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