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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').
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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

16160 results found.

  1. EP240708a: KAIT optical upper limit
  2. EP240708a: NOT optical observations
  3. EP240708a: SVOM/C-GFT optical upper limit
  4. EP240708a: Optical upper limits with Kinder observations
  5. EP240703b: GSP optical upper limit
  6. EP240703b: TRT optical upper limits
  7. EP240703a: TRT further optical observation
  8. EP240702a: TRT optical upper limits
  9. EP240703a: KAIT optical upper limit
  10. EP240703c: Kinder optical follow-up and Swift XRT observations
  11. EP240703a: BOOTES-3 optical upper limit
  12. EP240703a: Liverpool Telescope optical follow-up observations
  13. EP240703a/GRB 240703A: TRT optical candidate likely not real
  14. EP240703a: Kinder optical follow-up observations
  15. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  16. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  17. EP240702a: GSP optical upper limit
  18. EP240626a: Montarrenti Observatory optical upper limit
  19. EP240626a: KAIT optical upper limit
  20. EP240625a: GRANDMA Optical Upper Limits
  21. EP240626a: BOOTES-7 optical upper limit
  22. EP240625a: NOT optical counterpart candidate
  23. GRB240615A: Gemini-North observations of the BAT and XRT positions
  24. GRB240615A: Gemini-North observations of the BAT and XRT positions
  25. EP240618a: NOT further optical observations
  26. EP240618a: NOT optical counterpart candidate
  27. GRB 240529A: JinShan optical observations
  28. EP240618a: GSP optical upper limit
  29. GRB 240619A: Fermi GBM Observation
  30. GRB 240619A: GOTO candidate optical afterglow
  31. EP240618a: Abastumani optical observationsEP240618a
  32. GRB 240615A: NOT optical observations
  33. EP240618a: GRANDMA Optical Upper Limits
  34. EP240618a: TRT optical upper limit
  35. EP240617a: STEP/T80S optical limits
  36. GRB 240615A: possible transient detection from Wendelstein observations
  37. EP240618a: BOOTES-6/DPRT optical upper limit
  38. GRB240615A: 1.3m DFOT optical upper limit
  39. EP240617a: BOOTES-6/DPRT optical upper limit
  40. X-ray transient EP240414a: Chandra late time observation
  41. GRB 240615A: FLWO-1.2m optical upper limits
  42. GRB 240615A: GOTO optical upper limits
  43. GRB 240529A: LBT optical detection and late temporal decay
  44. GRB 240529A : MITSuME Akeno optical afterglow detection
  45. GRB 240607A: Fermi GBM detection of a very bright burst
  46. GRB 240529A: SAO RAS optical observations
  47. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  48. GRB 240529A: MASTER prompt OT detection
  49. GRB 240529A: continued SAO RAS optical observations
  50. GRB 240529A: OSN optical detection
  51. GRB 240529A: further SAO RAS optical observations
  52. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  53. LXT 240528A: GSP optical upper limit
  54. GRB 240529A: 1.3m DFOT Optical observations
  55. GRB 240529A : Mondy optical observations
  56. GRB 240529A: SAO RAS optical observations
  57. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  58. GRB 240529A: optical photometry from Konkoly
  59. GRB 240529A: GROWTH-India optical follow-up
  60. GRB 240529A: AKO Optical Afterglow Detection
  61. GRB 240529A: Skynet Optical Observations
  62. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  63. GRB240529A: BOOTES-6/DPRT optical detection
  64. GRB 240529A: NOT optical observations
  65. GRB 240529A: GOTO optical afterglow detection
  66. GRB 240529A: Swift detection of a burst with an optical counterpart
  67. EP240518a: GSP optical upper limit
  68. GRB 240516A: Swift/UVOT Upper Limits
  69. GRB 240516A ATCA radio observations
  70. IPN triangulation of GRB 240514B (short)
  71. GRB 240514E: A possible candidate BD-21 1074
  72. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  73. GRB 240516A: GOTO optical upper limit
  74. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  75. GRB 240514B: GOTO candidate optical counterpart
  76. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  77. GRB 240511A: J-band observations with WINTER
  78. GRB 240511A : MITSuME Akeno optical upper limits
  79. GRB 240511A: optical afterglow detection from the NOT
  80. EP240506a: Xinglong optical upper limit
  81. EP240506a: CrAO ZTSH optical upper limit
  82. EP240506a: Archival radio searching
  83. EP240506a: TRT optical upper limit
  84. EP240506a: BOOTES Network optical upper limit
  85. EP240506a: Optical upper limit with Kinder observations
  86. GRB 240502A: 1.3m DFOT Optical upper limit
  87. LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
  88. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs
  89. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  90. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  91. GRB 240502A: GOTO optical upper limit
  92. GRB 240415A 1.3m DFOT Optical upper limit
  93. GRB 240502C: GOTO possible optical counterpart candidates
  94. X-ray transient EP240414a: Detection of associated supernova
  95. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  96. LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
  97. EP240426b: AST3-2 optical upper limit
  98. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  99. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  100. LIGO/Virgo/KAGRA S240422ed: Archival radio detection of EP240426a

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