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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"
  1. Konus-Wind observation of GRB 150922A
  2. LIGO/VIRGO G184098 : classifications of transients from the LSQ observations
  3. GRB 150922A: Fermi GBM observation
  4. IPN Triangulation of GRB 150922A (short/hard)
  5. Konus-Wind observation of GRB 150919A
  6. IPN Triangulation of GRB 150919A (short / hard)
  7. LIGO/Virgo G184098: INTEGRAL search of temporally coincident prompt hard X-ray emission
  8. LIGO/Virgo G184098: transient search with VISTA
  9. ANTARES neutrino detection: Fermi GBM Observations
  10. Fermi GBM trigger bn150920977 is not due to a GRB
  11. LIGO/Virgo G184098: DESGW followup program
  12. LIGO/Virgo G184098: SkyMapper observations
  13. LIGO/Virgo G184098: TAROT network optical observations
  14. LIGO/Virgo G184098: La Silla - QUEST Followup
  15. LIGO/Virgo G184098: Swift follow-up observations
  16. LIGO/Virgo G184098: MWA Followup
  17. LIGO/Virgo G184098: DESGW followup program
  18. LIGO/Virgo G184098: Pan-STARRS1 observations of the northern sky region
  19. LIGO/Virgo observing run 1 (O1) starts 2015-09-18 15:00 UTC
  20. LIGO/Virgo G184098: Keck II DEIMOS Spectra of iPTF Optical Candidates
  21. LIGO/Virgo G184098: Nearby Galaxies in Error Circle
  22. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  23. LIGO/Virgo G184098: Observations from the TOROS collaboration
  24. LIGO/Virgo G184098: iPTF Optical Transient Candidates
  25. LIGO/Virgo G184098: VST-ESO PARANAL observations
  26. LIGO/Virgo G184098: Pan-STARRS1 observations of the northern sky region
  27. Instructions for reporting follow-up observations related to LIGO/Virgo G184098
  28. LIGO/Virgo G184098: observations by MASTER
  29. LIGO/Virgo G184098: TAROT La Silla Observatory optical observations (TZAC)
  30. LIGO/Virgo G184098: Swift follow-up observations
  31. LIGO/Virgo G184098: Burst candidate in LIGO engineering run data
  32. GRB 150915A: Swift-XRT refined Analysis
  33. GRB 150915A, Swift-BAT refined analysis
  34. GRB 150910A: AAO optical observations
  35. Konus-Wind observation of GRB 150911A
  36. GRB150915A : IRSF NIR upper limits
  37. GRB 000000: test of sernum on the original circular
  38. GRB 150915A: NOT observations of a brightening afterglow
  39. GRB 150915A: Swift UVOT upper limits
  40. GRB 150906B: Further analysis of the Konus-Wind data
  41. GRB 150910A: Mt. Terskol observatory optical observations
  42. GRB 150910A: TSHAO optical observations
  43. GRB 150915A: VLT/X-shooter redshift
  44. GRB 150915A: GROND detection of an optical counterpart candidate
  45. GRB 150915A: MASTER-NET optical observations
  46. GRB 150915A: Swift detection of a burst
  47. GRB 150910A: T100 observations
  48. GRB 150911A: GROND Upper Limits
  49. GRB 150910A: Continued RATIR Observations
  50. GRB 150907A: Swift-XRT afterglow detection
  51. GRB 150912A: Swift-XRT and UVOT observations
  52. GRB 150911A: Chuguev observatory upper limit
  53. GRB 150911A: Mt. Terskol observatory upper limit
  54. GRB 150911A: Khureltogot upper limit
  55. GRB 150910A: Mt. Terskol observatory optical observation
  56. Fermi GBM trigger 463890496/150914103 is not a GRB
  57. GRB 150912A: MITSuME Ishigakijima upper limits
  58. GRB 150911A: WHT optical imaging
  59. GRB 150910A: RATIR Observations
  60. GRB 150910A: MITSuME Ishigakijima Optical Observation after 2 days
  61. GRB 150912A: MASTER-IAC optical observations
  62. GRB 150912A: Fermi GBM observation
  63. GRB 150906B - NGC 3313 association: Constraints from Ep-Eiso and Ep-Liso Relations
  64. GRB 150912A: Swift ToO observations
  65. GRB 150906B: theoretical estimation of redshift and isotropic energy
  66. GRB150910A: P60 Observations
  67. GRB150911A: P60 Observations
  68. GRB 150911A: Swift/UVOT Upper Limits
  69. GRB 150911A: Swift-BAT refined analysis
  70. GRB 150912A: A long GRB detected by INTEGRAL
  71. GRB 150911A: Swift-XRT refined Analysis
  72. GRB 150910A: AAO optical observations
  73. GRB 150910A: MITSuME Ishigakijima Optical Observation after 1 day
  74. GRB 150910A: Chuguev observatory optical observations
  75. GRB 150911A: MITSuME Okayama upper limits
  76. GRB 150910A: VLA Detection
  77. GRB 150910A: continued SAO RAS optical observations
  78. GRB 150911A: Enhanced Swift-XRT position
  79. GRB150911A MITSuME Okayama Ks-band upper-limit
  80. GRB 150910A: TSHAO optical observations
  81. GRB 150911A: Swift detection of a burst
  82. GRB 150910A: NOT observations of the afterglow
  83. GRB 150910A: MITSuME Okayama Ks-band Observation
  84. GRB 150910A: GROND observation of the afterglow
  85. GRB 150910A: MITSuME Ishigakijima Optical Observation
  86. GRB 150910A: SAO RAS optical photometry
  87. GRB 150910A: Redshift from 10.4m GTC+OSIRIS
  88. GRB 150910A: Kast spectroscopy from 3m Shane telescope
  89. GRB 150910A: Swift-XRT refined Analysis
  90. GRB 150910A: Enhanced Swift-XRT position
  91. GRB 150910A: Swift/UVOT Detection of a Brightening Afterglow
  92. GRB 150910A: Nanshan optical observations
  93. GRB 150910A: Swift-BAT refined analysis
  94. GRB 150910A: MITSuME Okayama Optical Observation
  95. GRB 150910A: LCOGT FTN afterglow observations
  96. GRB 150910A: KAIT Optical Afterglow Detection
  97. GRB 150910A: Swift detection of a burst with an optical afterglow
  98. Short GRB 150906B: proximity to NGC 3313 galaxy group
  99. Swift Trigger 654954 is not an astrophysical event
  100. Fermi GBM trigger 463422723/150908689 is not a GRB

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