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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"

11763 results found.

  1. GRB 230628D: Fermi GBM Final Real-time Localization
  2. GRB 230628B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  3. LIGO/Virgo/KAGRA S230627c: Global MASTER-Net observations report
  4. LIGO/Virgo/Kagra S230627c: NED Galaxies in the Localization Volume
  5. Konus-Wind detection of GRB 230616A
  6. LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
  7. GRB 230625B: Swift/BAT-GUANO detection of a long burst
  8. GRB 230622A: Swift-BAT refined analysis
  9. ATLAS23msn/ZTF23aaoohpy/AT2023lcr: Zeiss-1000 of Koshka observatory optical observations
  10. MAXI GRB 230623A: MASTER optical observations
  11. GRB 230623A: MAXI/GSC detection
  12. Fermi GBM-230619: AstroSat CZTI non-detection and upper limits for the sub-threshold candidate
  13. IceCube-Cascade 230621A: Upper limits from a search for additional neutrino events in IceCube
  14. Fermi trigger No 709083929: Global MASTER-Net observations report
  15. AT2023lcr: VLA radio detection
  16. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
  17. LIGO/Virgo S230620ad: Global MASTER-Net observations report
  18. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  19. LIGO/Virgo S230620au: Global MASTER-Net observations report
  20. ZTF23aaoohpy/AT2023lc: Mondy optical observations
  21. IPN triangulation of GRB 230616A (short)
  22. AT2023lcr: Neil Gehrels Swift Observatory X-ray detection
  23. AT2023lcr: Pan-STARRS & ATLAS Observations
  24. ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
  25. ZTF23aaoohpy/AT2023lcr: Xinglong-2.16m optical observations
  26. LIGO/Virgo S230620al: Global MASTER-Net observations report
  27. LIGO/Virgo S230620af: Global MASTER-Net observations report
  28. LIGO/Virgo S230620z: Global MASTER-Net observations report
  29. LIGO/Virgo S230620w: Global MASTER-Net observations report
  30. LIGO/Virgo S230619bg: Global MASTER-Net observations report
  31. LIGO/Virgo S230620g: Global MASTER-Net observations report
  32. LIGO/Virgo S230619ay: Global MASTER-Net observations report
  33. LIGO/Virgo/KAGRA S230615az: GRANDMA observations of GOTO and GIT candidates
  34. LIGO/Virgo S230619e: Global MASTER-Net observations report
  35. LIGO/Virgo S230618at: Global MASTER-Net observations report
  36. GRB 230618A: Swift-XRT refined Analysis
  37. LIGO/Virgo S230618r: Global MASTER-Net observations report
  38. LIGO/Virgo S230616aa: Global MASTER-Net observations report
  39. LIGO/Virgo S230615ak: Global MASTER-Net observations report
  40. LIGO/Virgo S230618k: Global MASTER-Net observations report
  41. LIGO/Virgo S230617bc: Global MASTER-Net observations report
  42. LIGO/Virgo S230617aq: Global MASTER-Net observations report
  43. LIGO/Virgo S230617ab: Global MASTER-Net observations report
  44. Swift GRB 230618A: Global MASTER-Net observations report
  45. LIGO/Virgo S230617aj: Global MASTER-Net observations report
  46. GRB 230618A: Swift detection of a burst
  47. LIGO/Virgo/KAGRA S230615az: Non-Detections of GROWTH-India Candidates from GECKO Optical Observations
  48. GRB 230616A: AstroSat CZTI detection
  49. LIGO/Virgo S230616s: Global MASTER-Net observations report
  50. LIGO/Virgo/KAGRA S230615az: GROWTH-India candidates
  51. GRB 230614C: AstroSat CZTI detection
  52. LIGO/Virgo S230614ac: Global MASTER-Net observations report
  53. Fermi trigger No 708426906: Global MASTER-Net observations report
  54. LIGO/Virgo S230609u: Global MASTER-Net observations report
  55. GRB 230608A: AstroSat CZTI detection
  56. LIGO/Virgo S230608as: Global MASTER-Net observations report
  57. LIGO/Virgo S230609a: Global MASTER-Net observations report
  58. LIGO/Virgo S230608ah: Global MASTER-Net observations report
  59. LIGO/Virgo/KAGRA S230608as: Identification of a GW compact binary merger candidate
  60. Fermi trigger No 707039690: Global MASTER-Net observations report
  61. GRB 230606A: Swift-XRT refined Analysis
  62. GRB 230606A: Swift detection of a burst
  63. Fermi-LAT gamma-ray observations of IceCube-230603A
  64. GRB 230604A: AstroSat CZTI detection of a short GRB
  65. LIGO/Virgo S230603aa: Global MASTER-Net observations report
  66. LIGO/Virgo S230602ap: Global MASTER-Net observations report
  67. LIGO/Virgo S230601bf: Global MASTER-Net observations report
  68. LIGO/Virgo/KAGRA S230527ch: Zwicky Transient Facility observations
  69. LIGO/Virgo/KAGRA S230529ay: Upper limits from CALET observations.
  70. LIGO/Virgo/KAGRA S230529ay: AstroSat CZTI non-detection and upper limits
  71. LIGO/Virgo S230529ay: Global MASTER-Net observations report
  72. LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
  73. LIGO/Virgo S230525a: Global MASTER-Net observations report
  74. Fermi-LAT gamma-ray observations of IceCube-230524A
  75. GRB 230510A: Swift-BAT refined analysis
  76. GRB 230525A: Fermi GBM Final Localization
  77. IceCube Alert 230524.47: Global MASTER-Net observations report
  78. GRB 230524B: AstroSat CZTI detection
  79. GRB 230524A: AstroSat CZTI detection
  80. LIGO/Virgo S230524b: Global MASTER-Net observations report
  81. Fermi trigger No 706536788: Global MASTER-Net observations report
  82. LIGO/Virgo S230522a: Global MASTER-Net observations report
  83. LIGO/Virgo S230521k: Global MASTER-Net observations report
  84. LIGO/Virgo S230520ae: Global MASTER-Net observations report
  85. Fermi trigger No 706317104: Global MASTER-Net observations report
  86. GRB 230520A: CALET Gamma-Ray Burst Monitor detection
  87. LIGO/Virgo/KAGRA S230520ae: Identification of a GW compact binary merger candidate: End-to-End Test
  88. GRB 230520B is not a GRB
  89. GRB 230520B: Fermi GBM Final Real-time Localization
  90. LIGO/Virgo/KAGRA S230520ae: Upper limits from IceCube neutrino search
  91. LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
  92. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  93. GRB 230520A: MAXI/GSC detection
  94. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  95. LIGO/Virgo/KAGRA S230518h: Upper limits from Konus-Wind observations
  96. LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
  97. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  98. LIGO/Virgo/Kagra S230518h: NED Galaxies in the Localization Volume
  99. LIGO/Virgo/KAGRA S230518h: AstroSat CZTI non-detection and upper limits
  100. LIGO/Virgo S230518h: Global MASTER-Net observations report

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