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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"

3765 results found.

  1. GRB 160221A: MASTER-SAAO early observations
  2. GRB 160220A: MASTER-Amur observations
  3. LIGO/Virgo G211117: LOFAR follow-up
  4. GRB 160206A: MAXI/GSC detection
  5. GRB 160203A: TAROT La Silla - TAROT Calern - Zadko observations
  6. Fermi GBM trigger 475675010/160128498 is not a GRB
  7. GRB 160131A: Khureltogot optical observations
  8. GRB 160127A: LCOGT-Sutherland optical upper limit
  9. LIGO Virgo G211117: MWA Observations
  10. GRB160119A: BOOTES-2/TELMA Early Upper Limits
  11. GRB 160119A: Swift detection of a burst
  12. GRB 151228B: AbAO optical upper limit
  13. Konus-Wind observation of GRB 160113A
  14. IPN Triangulation of GRB 160113A
  15. LIGO/Virgo G211117: iPTF Observations of PS15dpn
  16. LIGO/Virgo G211117: VISTA imaging
  17. LIGO/Virgo G211117: Subaru Hyper Suprime-Cam follow-up observation
  18. GRB 160104A: MITSuME Okayama upper limits
  19. LIGO/Virgo G211117: Summary of Pan-STARRS transients
  20. LIGO/Virgo G211117: Gemini classification of 7 Pan-STARRS transients
  21. LIGO/Virgo G211117: LOFAR follow-up
  22. LIGO/Virgo G211117: PESSTO classification of Pan-STARRS transients
  23. LIGO/Virgo G211117: CSS/CRTS observations on 29/30 Dec 2015 UT
  24. GRB 160102A: MAXI/GSC detection
  25. LIGO/Virgo G211117: La Silla - QUEST observations 2015 Dec 28 - 30
  26. GRB 151231B: Fermi GBM observation
  27. LIGO/Virgo G211117: 44 transients from Pan-STARRS data during 2015-12-28/30
  28. LIGO/Virgo G211117: Liverpool Telescope followup of EM candidates
  29. LIGO/Virgo G211117: VLA follow-up
  30. Trigger 668877: Swift detection of V 404 Cyg
  31. LIGO/Virgo G211117: MAGIC very-high energy gamma-ray observations
  32. V404Cyg Swift Trigger 668097: CrAO RT-22 radio observations
  33. V404Cyg Swift Trigger 668097: AbAO optical observations
  34. LIGO/Virgo G211117: Optical Observations with Kiso Schmidt telescope and KWFC
  35. LIGO/Virgo G211117: List of near-term future observation regions by Project Mini-GWAC of SVOM
  36. LIGO/Virgo G211117: iPTF Optical Transient Candidates
  37. LIGO/Virgo G211117: La Silla - QUEST observations 2015 Dec 28, 29
  38. GRB 151228B: Fermi GBM observation
  39. GRB 151228A: MITSuME Akeno optical upper limits
  40. GRB 151228A: T60 observations
  41. LIGO/Virgo G211117: Optical NIR observation with Kanata telescope
  42. GRB 151228A: Fermi GBM observation
  43. LIGO/Virgo G211117: Pan-STARRS1 observations 2015-12-28
  44. LIGO/Virgo G211117: INAF VST-ESO PARANAL observations
  45. GRB 151215A: Swift detection of a burst
  46. GRB 151205C: Optical follow-up observations at Kiso
  47. GRB 130831A: MASTER early OT detection and LC
  48. GRB 151205B: MASTER-NET early optical observations
  49. GRB 151205B: Swift detection of a burst
  50. Fermi GBM trigger 470375959/151128166 is not a GRB
  51. GRB151127A: Planned XMM-Newton observation
  52. GRB 151120A: Swift-XRT afterglow detection
  53. GRB 151120A: GROND optical/NIR afterglow
  54. GRB 151118A: ISON-NM early optical limit
  55. Swift-BAT trigger 663164 is not a burst.
  56. GRB 151107B: MASTER-NET OT detection inside the FERMI error box
  57. LIGO/Virgo G194575: Liverpool Telescope observations of iPTF-15dld and iPTF-15dni
  58. GRB 151107A: MASTER-NET optical observations
  59. GRB 151027A: Mondy optical observations
  60. GRB 151027A: Mt. Terskol observatory optical observation
  61. LIGO/Virgo G194575: LT Spectroscopy of iPTF candidates
  62. GRB 151031A: Swift detection of a burst
  63. GRB 151027A: Continued P60 Monitoring
  64. GRB 151027A: Optical counterpart detection
  65. GRB 151027A: SAO RAS optical observations
  66. GRB 151027B: LCOGT FTN afterglow observations
  67. GRB 151027A : Xinglong TNT optical observation
  68. GRB 151027A: continued GMG observation
  69. GRB 151027A: LCOGT-McDonald afterglow observations
  70. GRB 151027B: GROND Optical/NIR Afterglow Detection
  71. GRB 151027B: VLT/X-shooter redshift
  72. LIGO/Virgo G194575: Kanata/J-GEM optical follow-up
  73. LIGO/Virgo G194575: CQUEAN/LOAO observations
  74. LIGO/Virgo G194575: more details on transients from Pan-STARRS in the RA=1hr localisation region
  75. LIGO/Virgo G194575: transients from Pan-STARRS in the RA=1hr localisation region
  76. Konus-Wind observation of GRB 151021A
  77. GRB 151001B: Swift-BAT refined analysis
  78. GRB 150925A: Swift detection of a burst
  79. LIGO/Virgo G184098: INTEGRAL search of temporally coincident prompt hard X-ray emission
  80. LIGO/Virgo G184098: DESGW followup program
  81. LIGO/Virgo G184098: Keck II DEIMOS Spectra of iPTF Optical Candidates
  82. GRB 150915A: GROND detection of an optical counterpart candidate
  83. Fermi GBM trigger 463890496/150914103 is not a GRB
  84. GRB 150910A: VLA Detection
  85. GRB 150910A: MITSuME Okayama Ks-band Observation
  86. GRB 150910A: Enhanced Swift-XRT position
  87. GRB 150910A: Swift/UVOT Detection of a Brightening Afterglow
  88. GRB 150910A: LCOGT FTN afterglow observations
  89. GRB 150910A: Swift detection of a burst with an optical afterglow
  90. GRB 150907B: MASTER-SAAO early optical observations
  91. GRB 150907A: MAXI/GSC detection
  92. GRB 150901A: Swift detection of a burst
  93. Fermi GBM trigger 150828520 is not a GRB
  94. Swift Trigger 652824 is due to noise
  95. Swift Trigger 652824: Is most likely a noise fluctuation in the direction of M31
  96. GRB 150818A: MITSuME Ishigakijima upper limits
  97. GRB 150818A: Swift/UVOT candidate afterglow
  98. GRB 150818A: Swift detection of a burst
  99. Konus-Wind observation of GRB 150811B
  100. Swift Trigger 652046 is probably not a GRB

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