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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"

20960 results found.

  1. GRB 151112A: GROND photometric redshift and i'-band prediction
  2. GRB 151114A: Swift/UVOT Detection
  3. GRB 151114A: LCOGT-FTS afterglow observations
  4. GRB 151111A: GROND confirmation of the afterglow and photometric redshift estimate
  5. GRB 151112A: Swift/UVOT Upper Limits
  6. GRB 151112A: GROND Detection of the Optical/NIR Afterglow Candidate
  7. GRB 151112A: initial UVOT observations
  8. GRB 151112A: Swift-XRT observations
  9. GRB 151111A: Swift/UVOT upper limits
  10. GRB 151111A: GROND marginal detection of a afterglow candidate
  11. LIGO/Virgo G194575: VLA follow-up
  12. GRB 151111A: LCOGT-FTS afterglow observations
  13. GRB 151107B: MASTER-NET OT detection inside the FERMI error box
  14. GRB 151027A: continued Mondy optical observations
  15. LIGO/Virgo G194575: Liverpool Telescope observations of iPTF-15dld and iPTF-15dni
  16. LIGO/Virgo G194575: La Silla QUEST, Pan-STARRS and PESSTO observations of iPTF15dld
  17. LIGO/Virgo G194575: Swift observations if iPTF15dld
  18. GRB 151027A: Hankasalmi optical observations
  19. LIGO/Virgo G194575: INAF-TNG/Asiago Telescope follow-up of iPTF15dld
  20. GRB 151107A: MASTER-NET optical observations
  21. LIGO/Virgo G194575: INAF-Asiago Telescope further analysis of iPTF candidates
  22. Swift-BAT triggers are disabled
  23. LIGO/Virgo G194575: INAF-Asiago Telescope follow-up of iPTF candidates
  24. LIGO/Virgo G194575: VLA follow-up
  25. GRB 151027A: Mondy optical observations
  26. GRB 150910A: CrAO optical observations
  27. GRB 151027A: Correction to GCN 18519
  28. GRB 151031A: GROND observation
  29. LIGO/Virgo G194575: LT Spectroscopy of iPTF candidates
  30. GRB 151031A: Swift/UVOT Detection
  31. GRB 151031A: VLT/X-shooter optical counterpart and redshift
  32. GRB 151027A: optical follow-up observations
  33. GRB 151027A: Continued P60 Monitoring
  34. GRB 151029A: Swift/UVOT Detection
  35. GRB 151029A: LCOGT-FTS afterglow observations
  36. GRB 151027B: Swift UVOT detection
  37. LIGO/Virgo G194575: VLA follow-up
  38. GRB 151027A: MAXI/GSC detection
  39. GRB 151029A VLT/X-shooter redshift
  40. GRB 151029A: GROND afterglow observations
  41. GRB 151027A: SAO RAS optical observations
  42. GRB 151027B: LCOGT FTN afterglow observations
  43. GRB 151027A: NOT optical and NIR observations
  44. GRB 151027A: T100 observations
  45. GRB 151027B: Swift/UVOT Upper Limits
  46. GRB 151027A : Xinglong TNT optical observation
  47. GRB 151027A: continued GMG observation
  48. GRB 151027B: RATIR Observations
  49. GRB 151027B: MASTER-NET early OT detection
  50. GRB 151027A: LCOGT-McDonald afterglow observations
  51. GRB 151027A: VLA detection
  52. GRB 151027B: GROND Optical/NIR Afterglow Detection
  53. GRB 151027B: VLT/X-shooter redshift
  54. GRB 151027A: THO optical observations
  55. GRB 151027A: UVOT Observations
  56. GRB 151027B: NOT optical afterglow candidate
  57. LIGO/Virgo G194575: iPTF Optical Transient Candidates
  58. GRB 151027A: Early RAPTOR Observations
  59. LIGO/Virgo G194575: MASTER Optical Inspection
  60. GRB 151027A: GMG observation
  61. LIGO/Virgo G194575: Swift observations of LSQ15bjb
  62. LIGO/Virgo G194575: GROND multi-color observations
  63. GRB 151027A: Weihai optical observations
  64. LIGO/Virgo G194575: further Pan-STARRS observations of the RA=1hr localisation region
  65. GRB 151027A: P60 afterglow confirmation and rebrightening
  66. GRB 151027A: KAIT optical afterglow confirmation
  67. LIGO/Virgo G194575: ASKAP followup
  68. LIGO/Virgo G194575: INAF-TNG follow-up of LSQ15bjb
  69. LIGO/Virgo G194575 : La Silla - QUEST followup
  70. GRB 151021A: Skynet PROMPT-CTIO/DSO17 observations of the optical afterglow
  71. LIGO/Virgo G194575: Near-infrared follow-up with OAO-WFC
  72. LIGO/Virgo G194575: Kanata/J-GEM optical follow-up
  73. LIGO/Virgo G194575: Pi of the Sky observations
  74. LIGO/Virgo G194575: MAXI/GSC observations
  75. LIGO/Virgo G194575: Swift observations
  76. GRB 151022A: OSN optical upper limit
  77. GRB 151023A: RATIR Observations
  78. GRB 151023A: Swift/UVOT Upper Limits
  79. GRB 151023A
  80. LIGO/Virgo G194575: CQUEAN/LOAO observations
  81. LIGO/Virgo G194575: LOFAR follow-up
  82. GRB 151022A: Swift/UVOT Upper Limits
  83. LIGO/Virgo G194575: RATIR Observations of Nearby Galaxies in the 1sigma Error Region
  84. LIGO Virgo G194575: MWA Observations
  85. LIGO/Virgo G194575: RATIR Observations of Nearby Galaxies in the 1sigma Error Region
  86. LIGO/Virgo G194575: more details on transients from Pan-STARRS in the RA=1hr localisation region
  87. LIGO/Virgo G194575: Fermi GBM Observations
  88. LIGO/Virgo G194575: Mini-MegaTORTORA observations
  89. LIGO/Virgo G194575: transients from Pan-STARRS in the RA=1hr localisation region
  90. LIGO Virgo G194575: TZAC TAROT observations
  91. GRB 151022A: MITSuME Okayama Ks-band upper-limit
  92. GRB 151022A: MASTER-Ural observations
  93. GRB 151021A: MITSuME Okayama Ks-band upper-limit
  94. GRB 151021A: Swift/UVOT Detection
  95. LIGO/Virgo G184098: LOFAR follow-up
  96. GRB 151004A: Swift-XRT follow-up observations
  97. Trigger 659734: Swift detection of SAX J1750.8-2900 or other source near Galactic center
  98. LIGO/Virgo G184098: VLA follow-up of iPTF15cyk
  99. LIGO/VIRGO G184098 : PESSTO classifications of PanSTARRS transients in the northern region
  100. GRB 151006A: OSN optical upper limit

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