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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"

43609 results found.

  1. LIGO/Virgo G184098: Nearby Galaxies in Error Circle
  2. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  3. LIGO/Virgo G184098: Observations from the TOROS collaboration
  4. LIGO/Virgo G184098: iPTF Optical Transient Candidates
  5. LIGO/Virgo G184098: Pan-STARRS1 observations of the northern sky region
  6. Instructions for reporting follow-up observations related to LIGO/Virgo G184098
  7. LIGO/Virgo G184098: observations by MASTER
  8. LIGO/Virgo G184098: TAROT La Silla Observatory optical observations (TZAC)
  9. LIGO/Virgo G184098: Swift follow-up observations
  10. LIGO/Virgo G184098: Burst candidate in LIGO engineering run data
  11. GRB 150915A: Swift-XRT refined Analysis
  12. GRB 150915A, Swift-BAT refined analysis
  13. GRB 150910A: AAO optical observations
  14. Konus-Wind observation of GRB 150911A
  15. GRB150915A : IRSF NIR upper limits
  16. GRB 000000: test of sernum on the original circular
  17. GRB 150915A: NOT observations of a brightening afterglow
  18. GRB 150915A: Swift UVOT upper limits
  19. GRB 150906B: Further analysis of the Konus-Wind data
  20. GRB 150910A: Mt. Terskol observatory optical observations
  21. GRB 150910A: TSHAO optical observations
  22. GRB 150915A: VLT/X-shooter redshift
  23. GRB 150915A: GROND detection of an optical counterpart candidate
  24. GRB 150915A: MASTER-NET optical observations
  25. GRB 150915A: Swift detection of a burst
  26. GRB 150910A: T100 observations
  27. GRB 150911A: GROND Upper Limits
  28. GRB 150910A: Continued RATIR Observations
  29. GRB 150907A: Swift-XRT afterglow detection
  30. GRB 150912A: Swift-XRT and UVOT observations
  31. GRB 150911A: Chuguev observatory upper limit
  32. GRB 150911A: Mt. Terskol observatory upper limit
  33. GRB 150911A: Khureltogot upper limit
  34. GRB 150910A: Mt. Terskol observatory optical observation
  35. Fermi GBM trigger 463890496/150914103 is not a GRB
  36. GRB 150911A: WHT optical imaging
  37. GRB 150910A: RATIR Observations
  38. GRB 150912A: MASTER-IAC optical observations
  39. GRB 150912A: Fermi GBM observation
  40. GRB 150906B - NGC 3313 association: Constraints from Ep-Eiso and Ep-Liso Relations
  41. GRB 150912A: Swift ToO observations
  42. GRB 150906B: theoretical estimation of redshift and isotropic energy
  43. GRB150910A: P60 Observations
  44. GRB150911A: P60 Observations
  45. GRB 150911A: Swift-BAT refined analysis
  46. GRB 150912A: A long GRB detected by INTEGRAL
  47. GRB 150911A: Swift-XRT refined Analysis
  48. GRB 150910A: AAO optical observations
  49. GRB 150910A: Chuguev observatory optical observations
  50. GRB 150910A: VLA Detection
  51. GRB 150910A: continued SAO RAS optical observations
  52. GRB 150911A: Enhanced Swift-XRT position
  53. GRB150911A MITSuME Okayama Ks-band upper-limit
  54. GRB 150910A: TSHAO optical observations
  55. GRB 150911A: Swift detection of a burst
  56. GRB 150910A: NOT observations of the afterglow
  57. GRB 150910A: MITSuME Okayama Ks-band Observation
  58. GRB 150910A: GROND observation of the afterglow
  59. GRB 150910A: Redshift from 10.4m GTC+OSIRIS
  60. GRB 150910A: Kast spectroscopy from 3m Shane telescope
  61. GRB 150910A: Swift-XRT refined Analysis
  62. GRB 150910A: Enhanced Swift-XRT position
  63. GRB 150910A: Swift/UVOT Detection of a Brightening Afterglow
  64. GRB 150910A: Nanshan optical observations
  65. GRB 150910A: Swift-BAT refined analysis
  66. GRB 150910A: LCOGT FTN afterglow observations
  67. GRB 150910A: Swift detection of a burst with an optical afterglow
  68. Short GRB 150906B: proximity to NGC 3313 galaxy group
  69. Swift Trigger 654954 is not an astrophysical event
  70. Fermi GBM trigger 463422723/150908689 is not a GRB
  71. GRB 150907B: Swift-XRT refined Analysis
  72. Konus-Wind observation of GRB 150906B
  73. IPN Triangulation of GRB 150906B (short/intense)
  74. Fermi GBM trigger 463339482/150907725 is too weak to be classified
  75. GRB 150907B: Swift-BAT refined analysis
  76. GRB 150907B: MASTER-SAAO early optical observations
  77. GRB 150907B: Enhanced Swift-XRT position
  78. GRB 150907B: GROND Upper Limits
  79. GRB 150907B: Swift-XRT observations
  80. GRB 150907A: Swift-XRT observations
  81. GRB 150907B: Swift detection of a burst
  82. Fermi GBM trigger 150907763 is not a GRB
  83. GRB 150907A: Tiled Swift observations
  84. GRB 150907A: MAXI/GSC detection
  85. GRB 150906A: Fermi GBM detection
  86. GRB 150818A: TSHAO and SAO RAS optical observations
  87. GRB 150902A: Swift-XRT afterglow detection
  88. ANTARES neutrino detection: ANU 2.3m and Kepler K2 Observations of the Swift x-ray source
  89. ANTARES neutrino detection: CAHA photometry & spectroscopy of the Swift source
  90. ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
  91. ANTARES neutrino detection and Swift/XRT counterpart: GMG observation
  92. GRB 150902A: Swift/UVOT Upper Limits
  93. GRB 150902A: Swift-XRT observations
  94. ANTARES neutrino detection: Optical/NIR spectroscopy of the Swift/XRT counterpart candidate from NOT
  95. GRB 150831A: 9.8 GHz VLA upper limits
  96. GRB 150902A: MASTER-SAAO optical observations
  97. Konus-Wind observation of GRB 150902A
  98. GRB 150901A, Swift-BAT refined analysis
  99. ANTARES neutrino detection and possible Swift X-ray counterpart
  100. GRB 150902A: Swift ToO observations

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