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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"

2722 results found.

  1. Swift GRB230818.98: Global MASTER-Net observations report
  2. IPN triangulation of GRB 230815B
  3. Fermi GRB 230814A: Global MASTER-Net observations report
  4. GRB 230812B: continued AbAO optical afterglow observations
  5. GRB 230812B: Optical observaions from Rozhen Observatory
  6. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  7. GRB 230812B: CrAO ZTSh optical observations
  8. GRB 230812B: Koshka Zeiss-1000 optical observations
  9. GRB 230812B: Leavitt Observatory optical observations
  10. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  11. GRB 230812B: AbAO optical observations
  12. GRB 230812B: Montarrenti Observatory optical observations
  13. GRB 230812B: Detected Optical Afterglow Candidate
  14. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  15. Fermi GRB 230812B: MASTER optical counterpart
  16. GRB 230812B: KAIT Optical Afterglow Candidate
  17. GRB 230812B: Improved Swift/XRT localization
  18. LAT GRB230812.79: Global MASTER-Net observations report
  19. Fermi GRB 230812B: Global MASTER-Net observations report
  20. Fermi trigger No 712991593: Global MASTER-Net observations report
  21. LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
  22. IceCube-230727A: No candidates from the Zwicky Transient Facility
  23. IceCube-230724A: No counterparts from the Zwicky Transient Facility
  24. LIGO/Virgo/KAGRA S230726b: one counterpart neutrino candidate from IceCube neutrino searches
  25. GRB 230725B: Fermi GBM Final Real-time Localization
  26. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  27. IceCube Alert 230724.08: Global MASTER-Net observations report
  28. Fermi trigger No 710741042: Global MASTER-Net observations report
  29. IceCube-230707A: No candidates from the Zwicky Transient Facility
  30. IceCube Alert 230708.35: Global MASTER-Net observations report
  31. Fermi GRB 230707A: Global MASTER-Net observations report
  32. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  33. LIGO/Virgo/KAGRA S230627c: GRANDMA observations of galaxies and ZTF counterpart candidates
  34. LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO
  35. Fermi GRB 230628D: Global MASTER-Net observations report
  36. GRB 230628E: Swift detection of a burst
  37. LIGO/Virgo/KAGRA S230627c: Additional observations from the Zwicky Transient Facility
  38. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  39. IceCube-Cascade 230621A: Upper limits from a search for additional neutrino events in IceCube
  40. Fermi trigger No 709083929: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S230619bg: one counterpart neutrino candidate from IceCube neutrino searches
  42. LIGO/Virgo/KAGRA S230615az: Wendelstein observations of DESI galaxies and GIT candidates
  43. ZTF23aaoohpy/AT2023lcr: Liverpool Telescope detection
  44. LIGO/Virgo S230619x: Global MASTER-Net observations report
  45. GRB 230616A: Swift-XRT observations
  46. LIGO/Virgo S230618r: Global MASTER-Net observations report
  47. LIGO/Virgo S230616aa: Global MASTER-Net observations report
  48. LIGO/Virgo S230615an: Global MASTER-Net observations report
  49. LIGO/Virgo S230618k: Global MASTER-Net observations report
  50. LIGO/Virgo S230618d: Global MASTER-Net observations report
  51. LIGO/Virgo S230617bc: Global MASTER-Net observations report
  52. LIGO/Virgo S230617aq: Global MASTER-Net observations report
  53. LIGO/Virgo S230617aj: Global MASTER-Net observations report
  54. GRB 230616A: AstroSat CZTI detection
  55. LIGO/Virgo/KAGRA S230615az: Xinglong-2.16m photometric observations of GIT candidates
  56. LIGO/Virgo S230616s: Global MASTER-Net observations report
  57. LIGO/Virgo S230615be: Global MASTER-Net observations report
  58. LIGO/Virgo S230615t: Global MASTER-Net observations report
  59. LIGO/Virgo S230611l: Global MASTER-Net observations report
  60. LIGO/Virgo S230609u: Global MASTER-Net observations report
  61. LIGO/Virgo S230609a: Global MASTER-Net observations report
  62. LIGO/Virgo S230608ah: Global MASTER-Net observations report
  63. Fermi trigger No 707039690: Global MASTER-Net observations report
  64. GRB 230506B: Chandra localization of the X-ray afterglow
  65. GRB 230522A: GRBAlpha and VZLUSAT-2 joint detection
  66. LIGO/Virgo S230601bf: Global MASTER-Net observations report
  67. LIGO/Virgo S230531f: Global MASTER-Net observations report
  68. LIGO/Virgo/KAGRA S230529ay: Upper limits from CALET observations.
  69. LIGO/Virgo S230529ay: Global MASTER-Net observations report
  70. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  71. LIGO/Virgo S230525a: Global MASTER-Net observations report
  72. IceCube Alert 230524.47: Global MASTER-Net observations report
  73. GRB 230524B: AstroSat CZTI detection
  74. LIGO/Virgo S230522a: Global MASTER-Net observations report
  75. LIGO/Virgo S230521k: Global MASTER-Net observations report
  76. LIGO/Virgo S230520ae: Global MASTER-Net observations report
  77. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  78. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  79. LIGO/Virgo S230518h: Global MASTER-Net observations report
  80. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  81. Fermi trigger No 705952199: Global MASTER-Net observations report
  82. GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  83. GRB 230512A: GRBAlpha detection
  84. GRB 230510A: OHP/T193 and OHP/T120 optical observations
  85. GRB 230512A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705565670)
  86. GRB 230430A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 704533643)
  87. GRB 230510A: Nanshan/NEXT optical afterglow detection
  88. GRB 230506B: Fermi GBM detection
  89. GRB 230506B: Swift detection of a burst
  90. GRB 230506B: Swift detection of a burst
  91. Fermi trigger No 704837952: Global MASTER-Net observations report
  92. Konus-Wind detection of GRB 230430A
  93. IPN triangulation of GRB 230430A (short)
  94. GRB 230430A: Fermi GBM observation
  95. GRB 230430A: AstroSat CZTI detection
  96. GRB 230430A: Fermi GBM Final Real-time Localization
  97. Fermi trigger No 704365743: Global MASTER-Net observations report
  98. GRB 230427A : OHP/T193 optical upper limit
  99. GRB 230426A: Fermi GBM Detection
  100. Fermi GRB 230409C: Global MASTER-Net observations report

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