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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"

3116 results found.

  1. GRB 230812B: Detected Optical Afterglow Candidate
  2. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  3. Fermi GRB 230812B: MASTER optical counterpart
  4. GRB 230812B: KAIT Optical Afterglow Candidate
  5. GRB 230812B: Improved Swift/XRT localization
  6. LAT GRB230812.79: Global MASTER-Net observations report
  7. Fermi GRB 230812B: Global MASTER-Net observations report
  8. Fermi trigger No 712991593: Global MASTER-Net observations report
  9. LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
  10. IceCube-230727A: No candidates from the Zwicky Transient Facility
  11. IceCube-230724A: No counterparts from the Zwicky Transient Facility
  12. LIGO/Virgo/KAGRA S230726b: one counterpart neutrino candidate from IceCube neutrino searches
  13. GRB 230725B: Fermi GBM Final Real-time Localization
  14. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  15. IceCube Alert 230724.08: Global MASTER-Net observations report
  16. Fermi trigger No 710741042: Global MASTER-Net observations report
  17. IceCube-230707A: No candidates from the Zwicky Transient Facility
  18. IceCube Alert 230708.35: Global MASTER-Net observations report
  19. Fermi GRB 230707A: Global MASTER-Net observations report
  20. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  21. LIGO/Virgo/KAGRA S230627c: GRANDMA observations of galaxies and ZTF counterpart candidates
  22. LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO
  23. Fermi GRB 230628D: Global MASTER-Net observations report
  24. GRB 230628E: Swift detection of a burst
  25. LIGO/Virgo/KAGRA S230627c: Additional observations from the Zwicky Transient Facility
  26. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  27. IceCube-Cascade 230621A: Upper limits from a search for additional neutrino events in IceCube
  28. Fermi trigger No 709083929: Global MASTER-Net observations report
  29. LIGO/Virgo/KAGRA S230619bg: one counterpart neutrino candidate from IceCube neutrino searches
  30. LIGO/Virgo/KAGRA S230615az: Wendelstein observations of DESI galaxies and GIT candidates
  31. ZTF23aaoohpy/AT2023lcr: Liverpool Telescope detection
  32. LIGO/Virgo S230619x: Global MASTER-Net observations report
  33. GRB 230616A: Swift-XRT observations
  34. LIGO/Virgo S230618r: Global MASTER-Net observations report
  35. LIGO/Virgo S230616aa: Global MASTER-Net observations report
  36. LIGO/Virgo S230615an: Global MASTER-Net observations report
  37. LIGO/Virgo S230618k: Global MASTER-Net observations report
  38. LIGO/Virgo S230618d: Global MASTER-Net observations report
  39. LIGO/Virgo S230617bc: Global MASTER-Net observations report
  40. LIGO/Virgo S230617aq: Global MASTER-Net observations report
  41. LIGO/Virgo S230617aj: Global MASTER-Net observations report
  42. GRB 230616A: AstroSat CZTI detection
  43. LIGO/Virgo/KAGRA S230615az: Xinglong-2.16m photometric observations of GIT candidates
  44. LIGO/Virgo S230616s: Global MASTER-Net observations report
  45. LIGO/Virgo S230615be: Global MASTER-Net observations report
  46. LIGO/Virgo S230615t: Global MASTER-Net observations report
  47. LIGO/Virgo S230611l: Global MASTER-Net observations report
  48. LIGO/Virgo S230609u: Global MASTER-Net observations report
  49. LIGO/Virgo S230609a: Global MASTER-Net observations report
  50. LIGO/Virgo S230608ah: Global MASTER-Net observations report
  51. Fermi trigger No 707039690: Global MASTER-Net observations report
  52. GRB 230506B: Chandra localization of the X-ray afterglow
  53. GRB 230522A: GRBAlpha and VZLUSAT-2 joint detection
  54. LIGO/Virgo S230601bf: Global MASTER-Net observations report
  55. LIGO/Virgo S230531f: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S230529ay: Upper limits from CALET observations.
  57. LIGO/Virgo S230529ay: Global MASTER-Net observations report
  58. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  59. LIGO/Virgo S230525a: Global MASTER-Net observations report
  60. IceCube Alert 230524.47: Global MASTER-Net observations report
  61. GRB 230524B: AstroSat CZTI detection
  62. LIGO/Virgo S230522a: Global MASTER-Net observations report
  63. LIGO/Virgo S230521k: Global MASTER-Net observations report
  64. LIGO/Virgo S230520ae: Global MASTER-Net observations report
  65. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  66. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  67. LIGO/Virgo S230518h: Global MASTER-Net observations report
  68. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  69. Fermi trigger No 705952199: Global MASTER-Net observations report
  70. GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  71. GRB 230512A: GRBAlpha detection
  72. GRB 230510A: OHP/T193 and OHP/T120 optical observations
  73. GRB 230512A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705565670)
  74. GRB 230430A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 704533643)
  75. GRB 230510A: Nanshan/NEXT optical afterglow detection
  76. GRB 230506B: Fermi GBM detection
  77. GRB 230506B: Swift detection of a burst
  78. GRB 230506B: Swift detection of a burst
  79. Fermi trigger No 704837952: Global MASTER-Net observations report
  80. Konus-Wind detection of GRB 230430A
  81. IPN triangulation of GRB 230430A (short)
  82. GRB 230430A: Fermi GBM observation
  83. GRB 230430A: AstroSat CZTI detection
  84. GRB 230430A: Fermi GBM Final Real-time Localization
  85. Fermi trigger No 704365743: Global MASTER-Net observations report
  86. GRB 230427A : OHP/T193 optical upper limit
  87. GRB 230426A: Fermi GBM Detection
  88. Fermi GRB 230409C: Global MASTER-Net observations report
  89. GRB 230405B: Prompt enhanced Swift-XRT position
  90. GRB 230328B: Fermi GBM Final Real-time Localization
  91. GRB 230325A: X-shooter optical afterglow and redshift
  92. GRB 230325A: Prompt enhanced Swift-XRT position
  93. GRB 230322B: Swift/UVOT Detection
  94. Konus-Wind detection of GRB 230308A
  95. GRB 230322B: Swift detection of a burst with optical counterpart
  96. Fermi trigger No 701058254: Global MASTER-Net observations report
  97. GRB 230314A: TURBO Optical Upper Limit
  98. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  99. Fermi trigger No 700976129: Global MASTER-Net observations report
  100. GRB 230314A: Fermi GBM Final Real-time Localization

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