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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"

22056 results found.

  1. LIGO/Virgo S230621ad: Global MASTER-Net observations report
  2. LIGO/Virgo/KAGRA S230615az: LBT spectroscopic redshift of the host galaxy of GOTO23hn
  3. ZTF23aaoohpy/AT2023lcr: SAO RAS observations
  4. Fermi trigger No 709083929: Global MASTER-Net observations report
  5. AT2023lcr: VLA radio detection
  6. ZTF23aaoohpy/AT2023lcr: Montarrenti Observatory optical observations
  7. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
  8. LIGO/Virgo S230620ad: Global MASTER-Net observations report
  9. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  10. LIGO/Virgo S230620au: Global MASTER-Net observations report
  11. ZTF23aaoohpy/AT2023lc: Mondy optical observations
  12. AT2023lcr: Neil Gehrels Swift Observatory X-ray detection
  13. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): Kinder observations with Lulin observatory and a probable plateau in the g-band light curve
  14. AT2023lcr: Pan-STARRS & ATLAS Observations
  15. ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
  16. ZTF23aaoohpy/AT2023lcr: Xinglong-2.16m optical observations
  17. LIGO/Virgo/KAGRA S230615az: Wendelstein observations of DESI galaxies and GIT candidates
  18. LIGO/Virgo S230620al: Global MASTER-Net observations report
  19. LIGO/Virgo S230620af: Global MASTER-Net observations report
  20. LIGO/Virgo S230620z: Global MASTER-Net observations report
  21. LIGO/Virgo S230620w: Global MASTER-Net observations report
  22. LIGO/Virgo S230619bg: Global MASTER-Net observations report
  23. LIGO/Virgo S230620g: Global MASTER-Net observations report
  24. LIGO/Virgo S230619ay: Global MASTER-Net observations report
  25. ZTF23aaoohpy/AT2023lcr: Liverpool Telescope detection
  26. ZTF23aaoohpy/AT2023lcr: OHP/T193 and OHP/T120 optical follow-up observations
  27. LIGO/Virgo S230619bd: Global MASTER-Net observations report
  28. LIGO/Virgo S230619bb: Global MASTER-Net observations report
  29. LIGO/Virgo S230619as: Global MASTER-Net observations report
  30. LIGO/Virgo S230619ap: Global MASTER-Net observations report
  31. ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
  32. GRB 230618A: Osservatorio Astronomico Nastro verde upper limit
  33. ZTF23aaoohpy/AT2023lcr: GOTO early optical observations and constraint
  34. ZTF23aaoohpy/AT2023lcr: Zwicky Transient Facility discovery of a fast fading red transient
  35. LIGO/Virgo S230619i: Global MASTER-Net observations report
  36. LIGO/Virgo/KAGRA S230615az: GRANDMA observations of GOTO and GIT candidates
  37. LIGO/Virgo S230619aa: Global MASTER-Net observations report
  38. LIGO/Virgo S230619x: Global MASTER-Net observations report
  39. LIGO/Virgo S230619e: Global MASTER-Net observations report
  40. LIGO/Virgo S230618at: Global MASTER-Net observations report
  41. LIGO/Virgo S230618ba: Global MASTER-Net observations report
  42. LIGO/Virgo S230618az: Global MASTER-Net observations report
  43. LIGO/Virgo S230618ae: Global MASTER-Net observations report
  44. LIGO/Virgo S230618aq: Global MASTER-Net observations report
  45. LIGO/Virgo S230618y: Global MASTER-Net observations report
  46. LIGO/Virgo S230618s: Global MASTER-Net observations report
  47. GRB 230618A: Swift/UVOT Upper Limits
  48. GRB 230616A: Swift-XRT observations
  49. LIGO/Virgo S230618r: Global MASTER-Net observations report
  50. LIGO/Virgo S230616aa: Global MASTER-Net observations report
  51. LIGO/Virgo S230615an: Global MASTER-Net observations report
  52. LIGO/Virgo S230615ak: Global MASTER-Net observations report
  53. GRB 230618A: KAIT Optical Observations
  54. LIGO/Virgo S230617ba: Global MASTER-Net observations report
  55. LIGO/Virgo S230618k: Global MASTER-Net observations report
  56. LIGO/Virgo S230618d: Global MASTER-Net observations report
  57. LIGO/Virgo S230617bc: Global MASTER-Net observations report
  58. LIGO/Virgo S230617aq: Global MASTER-Net observations report
  59. LIGO/Virgo S230617ab: Global MASTER-Net observations report
  60. Swift GRB 230618A: Global MASTER-Net observations report
  61. LIGO/Virgo S230617aj: Global MASTER-Net observations report
  62. GRB230618A: LCOGT Optical Observations
  63. GRB 230616A: Swift ToO observations
  64. LIGO/Virgo/KAGRA S230615az: T80S Search and Candidate Counterpart Identification
  65. LIGO/Virgo/KAGRA S230615az: Non-Detections of GROWTH-India Candidates from GECKO Optical Observations
  66. GRB 230616A: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  67. LIGO/Virgo/KAGRA S230615az: Xinglong-2.16m photometric observations of GIT candidates
  68. LIGO/Virgo/KAGRA S230615az: GOTO candidate counterparts
  69. LIGO/Virgo S230616s: Global MASTER-Net observations report
  70. LIGO/Virgo S230615be: Global MASTER-Net observations report
  71. LIGO/Virgo S230615af: Global MASTER-Net observations report
  72. LIGO/Virgo S230616j: Global MASTER-Net observations report
  73. LIGO/Virgo S230615av: Global MASTER-Net observations report
  74. LIGO/Virgo S230615az: Global MASTER-Net observations report
  75. LIGO/Virgo S230615ax: Global MASTER-Net observations report
  76. LIGO/Virgo S230615k: Global MASTER-Net observations report
  77. LIGO/Virgo S230615t: Global MASTER-Net observations report
  78. LIGO/Virgo S230615i: Global MASTER-Net observations report
  79. LIGO/Virgo S230613at: Global MASTER-Net observations report
  80. LIGO/Virgo S230614ac: Global MASTER-Net observations report
  81. LIGO/Virgo S230614t: Global MASTER-Net observations report
  82. LIGO/Virgo S230614o: Global MASTER-Net observations report
  83. GRB 230614B: Swift/BAT-GUANO detection outside the coded FOV
  84. Fermi trigger No 708426906: Global MASTER-Net observations report
  85. GRB 230606A: LCOGT Optical Observations
  86. LIGO/Virgo S230611be: Global MASTER-Net observations report
  87. LIGO/Virgo S230611l: Global MASTER-Net observations report
  88. LIGO/Virgo S230609u: Global MASTER-Net observations report
  89. LIGO/Virgo S230608aw: Global MASTER-Net observations report
  90. LIGO/Virgo S230608as: Global MASTER-Net observations report
  91. LIGO/Virgo S230609a: Global MASTER-Net observations report
  92. LIGO/Virgo S230608ah: Global MASTER-Net observations report
  93. LIGO/Virgo S230608q: Global MASTER-Net observations report
  94. ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
  95. Fermi GRB 230603A: Global MASTER-Net observations report
  96. Fermi trigger No 707039690: Global MASTER-Net observations report
  97. ZTF and GIT Observations of the Candidate Optical Afterglow AT2023jxk
  98. LIGO/Virgo/KAGRA S230602ap: Zwicky Transient Facility observations
  99. GRB 230606A: Swift/UVOT Upper Limits
  100. LIGO/Virgo S230606z: Global MASTER-Net observations report

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