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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"

41700 results found.

  1. Swift Trigger 657564: MASTER-NET early optical observations.
  2. Swift Trigger 657564: XRT prompt analysis
  3. LIGO/Virgo G184098: MASTER OTs detection and Scenario Machine prediction
  4. Swift Trigger 657564: a probable GRB
  5. LIGO/Virgo G184098: Ongoing gravitational-wave analysis
  6. GRB 151001A: Swift-BAT refined analysis
  7. GRB 151001A: RATIR Observations
  8. GRB 151001B: Swift/UVOT Upper Limits
  9. GRB 151001B: Swift-XRT refined Analysis
  10. GRB 151001B: Swift-BAT refined analysis
  11. GRB 151001A: Swift/UVOT Detection
  12. GRB 151001B: MASTER-NET early optical observations.
  13. GRB 151001A: NOT imaging
  14. GRB 151001A: Swift-XRT refined Analysis
  15. GRB 151001A: Fermi GBM detection
  16. GRB 151001B: Swift detection of a burst
  17. GRB 151001A: Swift detection of a burst with an optical counterpart
  18. LIGO/Virgo G184098: spectral classification of PS15cci
  19. LIGO/Virgo G184098: Update to LT Spectroscopy of PS15ccx
  20. LIGO/Virgo G184098: Liverpool Telescope Spectroscopy of PS15ccx
  21. GRB 150925A: Swift/UVOT Upper Limits
  22. GRB 150925A: Swift-BAT refined analysis
  23. GRB 150925A: Swift-XRT refined Analysis
  24. GRB 150925A: Swift detection of a burst
  25. LIGO/Virgo G184098: LOFAR follow-up
  26. LIGO/Virgo G184098: ASKAP followup
  27. LIGO/Virgo G184098: ongoing Pan-STARRS search for optical transients
  28. LIGO/Virgo G184098: optical transient search with Kiso Schmidt telescope and KWFC on behalf of J-GEM collaboration
  29. Konus-Wind observation of GRB 150922A
  30. LIGO/VIRGO G184098 : classifications of transients from the LSQ observations
  31. GRB 150922A: Fermi GBM observation
  32. IPN Triangulation of GRB 150922A (short/hard)
  33. Konus-Wind observation of GRB 150919A
  34. IPN Triangulation of GRB 150919A (short / hard)
  35. LIGO/Virgo G184098: INTEGRAL search of temporally coincident prompt hard X-ray emission
  36. LIGO/Virgo G184098: transient search with VISTA
  37. ANTARES neutrino detection: Fermi GBM Observations
  38. Fermi GBM trigger bn150920977 is not due to a GRB
  39. LIGO/Virgo G184098: DESGW followup program
  40. LIGO/Virgo G184098: SkyMapper observations
  41. LIGO/Virgo G184098: TAROT network optical observations
  42. LIGO/Virgo G184098: La Silla - QUEST Followup
  43. LIGO/Virgo G184098: Swift follow-up observations
  44. LIGO/Virgo G184098: MWA Followup
  45. LIGO/Virgo G184098: DESGW followup program
  46. LIGO/Virgo G184098: Pan-STARRS1 observations of the northern sky region
  47. LIGO/Virgo observing run 1 (O1) starts 2015-09-18 15:00 UTC
  48. LIGO/Virgo G184098: Keck II DEIMOS Spectra of iPTF Optical Candidates
  49. LIGO/Virgo G184098: Nearby Galaxies in Error Circle
  50. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  51. LIGO/Virgo G184098: Observations from the TOROS collaboration
  52. LIGO/Virgo G184098: iPTF Optical Transient Candidates
  53. LIGO/Virgo G184098: VST-ESO PARANAL observations
  54. LIGO/Virgo G184098: Pan-STARRS1 observations of the northern sky region
  55. Instructions for reporting follow-up observations related to LIGO/Virgo G184098
  56. LIGO/Virgo G184098: observations by MASTER
  57. LIGO/Virgo G184098: TAROT La Silla Observatory optical observations (TZAC)
  58. LIGO/Virgo G184098: Swift follow-up observations
  59. LIGO/Virgo G184098: Burst candidate in LIGO engineering run data
  60. GRB 150915A: Swift-XRT refined Analysis
  61. GRB 150915A, Swift-BAT refined analysis
  62. GRB 150910A: AAO optical observations
  63. Konus-Wind observation of GRB 150911A
  64. GRB150915A : IRSF NIR upper limits
  65. GRB 150915A: NOT observations of a brightening afterglow
  66. GRB 150915A: Swift UVOT upper limits
  67. GRB 150906B: Further analysis of the Konus-Wind data
  68. GRB 150910A: Mt. Terskol observatory optical observations
  69. GRB 150910A: TSHAO optical observations
  70. GRB 150915A: VLT/X-shooter redshift
  71. GRB 150915A: GROND detection of an optical counterpart candidate
  72. GRB 150915A: MASTER-NET optical observations
  73. GRB 150915A: Swift detection of a burst
  74. GRB 150910A: T100 observations
  75. GRB 150911A: GROND Upper Limits
  76. GRB 150910A: Continued RATIR Observations
  77. GRB 150907A: Swift-XRT afterglow detection
  78. GRB 150912A: Swift-XRT and UVOT observations
  79. GRB 150911A: Chuguev observatory upper limit
  80. GRB 150911A: Mt. Terskol observatory upper limit
  81. GRB 150911A: Khureltogot upper limit
  82. GRB 150910A: Mt. Terskol observatory optical observation
  83. Fermi GBM trigger 463890496/150914103 is not a GRB
  84. GRB 150912A: MITSuME Ishigakijima upper limits
  85. GRB 150911A: WHT optical imaging
  86. GRB 150910A: RATIR Observations
  87. GRB 150910A: MITSuME Ishigakijima Optical Observation after 2 days
  88. GRB 150912A: MASTER-IAC optical observations
  89. GRB 150912A: Fermi GBM observation
  90. GRB 150906B - NGC 3313 association: Constraints from Ep-Eiso and Ep-Liso Relations
  91. GRB 150912A: Swift ToO observations
  92. GRB 150906B: theoretical estimation of redshift and isotropic energy
  93. GRB150910A: P60 Observations
  94. GRB150911A: P60 Observations
  95. GRB 150911A: Swift/UVOT Upper Limits
  96. GRB 150911A: Swift-BAT refined analysis
  97. GRB 150912A: A long GRB detected by INTEGRAL
  98. GRB 150911A: Swift-XRT refined Analysis
  99. GRB 150910A: AAO optical observations
  100. GRB 150910A: MITSuME Ishigakijima Optical Observation after 1 day

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