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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB230626A: Fermi GBM Detection
  2. LIGO/Virgo/KAGRA S230627c: Global MASTER-Net observations report
  3. LIGO/Virgo/Kagra S230627c: NED Galaxies in the Localization Volume
  4. Konus-Wind detection of GRB 230616A
  5. LIGO/Virgo/KAGRA S230627c: Correction to HasMassGap probability
  6. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  7. LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
  8. LIGO/Virgo/KAGRA S230627c: Updated Sky localization and EM Bright Classification
  9. LIGO/Virgo/KAGRA S230627c: Identification of a GW compact binary merger candidate
  10. GRB 230618A: Swift-BAT refined analysis
  11. GRB 230625B: Swift/BAT-GUANO detection of a long burst
  12. LIGO/Virgo/KAGRA S230624av: Updated Sky localization
  13. GRB 230622A: Swift-BAT refined analysis
  14. GRB 230623A: Swift-XRT observations
  15. GRB 230625A: Fermi GBM Final Real-time Localization
  16. INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
  17. ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
  18. ATLAS23msn/ZTF23aaoohpy/AT2023lcr: Zeiss-1000 of Koshka observatory optical observations
  19. GRB 230623B: Swift/BAT-GUANO detection of a long burst outside the coded FOV 
  20. LIGO/Virgo/KAGRA S230624av: Identification of a GW compact binary merger candidate
  21. IceCube-Cascade 230622A: Upper limits from a search for additional neutrino events in IceCube
  22. GRB 230623A: Tiled Swift observations
  23. MAXI GRB 230623A: MASTER optical observations
  24. GRB 230623A: Tiled Swift observations
  25. GRB 230622A: ATCA rapid radio follow-up
  26. GRB 230622A: Swift-XRT refined Analysis
  27. GRB 230623A: MAXI/GSC detection
  28. Swift GRB 230622A: Global MASTER-Net observations report
  29. LIGO/Virgo/KAGRA S230615az: LBT spectroscopic classification of GOTO23hn
  30. LIGO/Virgo/KAGRA S230622ba: Retraction of GW compact binary merger candidate
  31. LIGO/Virgo S230622e: Global MASTER-Net observations report
  32. LIGO/Virgo S230621bq: Global MASTER-Net observations report
  33. LIGO/Virgo S230621ad: Global MASTER-Net observations report
  34. LIGO/Virgo/KAGRA S230615az: LBT spectroscopic redshift of the host galaxy of GOTO23hn
  35. ZTF23aaoohpy/AT2023lcr: SAO RAS observations
  36. Fermi GBM-230619: AstroSat CZTI non-detection and upper limits for the sub-threshold candidate
  37. GRB 230622A: Swift detection of a burst
  38. IceCube-Cascade 230621A: Upper limits from a search for additional neutrino events in IceCube
  39. GRB 230621A: Fermi GBM Final Localization Correction
  40. Fermi trigger No 709083929: Global MASTER-Net observations report
  41. Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  42. AT2023lcr: VLA radio detection
  43. ZTF23aaoohpy/AT2023lcr: Montarrenti Observatory optical observations
  44. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
  45. LIGO/Virgo S230620ad: Global MASTER-Net observations report
  46. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  47. LIGO/Virgo S230620au: Global MASTER-Net observations report
  48. ZTF23aaoohpy/AT2023lc: Mondy optical observations
  49. IPN triangulation of GRB 230616A (short)
  50. LIGO/Virgo/KAGRA S230619bg: one counterpart neutrino candidate from IceCube neutrino searches
  51. AT2023lcr: Neil Gehrels Swift Observatory X-ray detection
  52. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): Kinder observations with Lulin observatory and a probable plateau in the g-band light curve
  53. AT2023lcr: Pan-STARRS & ATLAS Observations
  54. ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
  55. ZTF23aaoohpy/AT2023lcr: Xinglong-2.16m optical observations
  56. LIGO/Virgo/KAGRA S230615az: Wendelstein observations of DESI galaxies and GIT candidates
  57. LIGO/Virgo S230620al: Global MASTER-Net observations report
  58. LIGO/Virgo S230620af: Global MASTER-Net observations report
  59. LIGO/Virgo S230620z: Global MASTER-Net observations report
  60. LIGO/Virgo S230620w: Global MASTER-Net observations report
  61. LIGO/Virgo S230619bg: Global MASTER-Net observations report
  62. LIGO/Virgo S230620g: Global MASTER-Net observations report
  63. LIGO/Virgo S230619ay: Global MASTER-Net observations report
  64. ZTF23aaoohpy/AT2023lcr: Liverpool Telescope detection
  65. ZTF23aaoohpy/AT2023lcr: OHP/T193 and OHP/T120 optical follow-up observations
  66. LIGO/Virgo S230619bd: Global MASTER-Net observations report
  67. LIGO/Virgo S230619bb: Global MASTER-Net observations report
  68. LIGO/Virgo S230619as: Global MASTER-Net observations report
  69. LIGO/Virgo S230619ap: Global MASTER-Net observations report
  70. ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
  71. GRB 230618A: Osservatorio Astronomico Nastro verde upper limit
  72. ZTF23aaoohpy/AT2023lcr: GOTO early optical observations and constraint
  73. ZTF23aaoohpy/AT2023lcr: Zwicky Transient Facility discovery of a fast fading red transient
  74. LIGO/Virgo S230619i: Global MASTER-Net observations report
  75. LIGO/Virgo/KAGRA S230615az: GRANDMA observations of GOTO and GIT candidates
  76. LIGO/Virgo S230619aa: Global MASTER-Net observations report
  77. LIGO/Virgo S230619x: Global MASTER-Net observations report
  78. LIGO/Virgo S230619e: Global MASTER-Net observations report
  79. LIGO/Virgo S230618at: Global MASTER-Net observations report
  80. LIGO/Virgo S230618ba: Global MASTER-Net observations report
  81. LIGO/Virgo S230618az: Global MASTER-Net observations report
  82. LIGO/Virgo S230618ae: Global MASTER-Net observations report
  83. LIGO/Virgo S230618aq: Global MASTER-Net observations report
  84. LIGO/Virgo S230618y: Global MASTER-Net observations report
  85. LIGO/Virgo S230618s: Global MASTER-Net observations report
  86. GRB 230618A: Enhanced Swift-XRT position
  87. GRB 230618A: Swift/UVOT Upper Limits
  88. GRB 230618A: Swift-XRT refined Analysis
  89. GRB 230616A: Swift-XRT observations
  90. LIGO/Virgo S230618r: Global MASTER-Net observations report
  91. LIGO/Virgo S230616aa: Global MASTER-Net observations report
  92. LIGO/Virgo S230615an: Global MASTER-Net observations report
  93. LIGO/Virgo S230615ak: Global MASTER-Net observations report
  94. GRB 230618A: KAIT Optical Observations
  95. LIGO/Virgo S230617ba: Global MASTER-Net observations report
  96. LIGO/Virgo S230618k: Global MASTER-Net observations report
  97. LIGO/Virgo S230618d: Global MASTER-Net observations report
  98. LIGO/Virgo S230617bc: Global MASTER-Net observations report
  99. LIGO/Virgo S230617aq: Global MASTER-Net observations report
  100. LIGO/Virgo S230617ab: Global MASTER-Net observations report

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