Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. See news and announcements

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"

2853 results found.

  1. LIGO/Virgo G211117: iPTF Optical Transient Candidates
  2. GRB 151229A: Swift detection of a short burst
  3. LIGO/Virgo G211117: Optical NIR observation with Kanata telescope
  4. LIGO/Virgo G211117: Optical follow-up with Kanata telescope
  5. GRB 151222A: Fermi GBM detection
  6. GRB 151210B: Fermi GBM observation
  7. GRB151215A: Early optical light curve from pt5m, La Palma
  8. GRB 151205C: Optical follow-up observations at Kiso
  9. GRB 151205C: MAXI/GSC detection
  10. GRB 151118A: Early optical limit from pt5m, La Palma
  11. GRB 151027A: SAO RAS and Mt. Terskol observations
  12. GRB GRB 151118A: MASTER-NET optical observations
  13. GRB 151107B: MASTER-NET OT detection inside the FERMI error box
  14. GRB 151031A: GROND observation
  15. LIGO/Virgo G194575: Near-infrared follow-up with OAO-WFC
  16. LIGO/Virgo G194575: Kanata/J-GEM optical follow-up
  17. LIGO/Virgo G194575: CQUEAN/LOAO observations
  18. LIGO Virgo G194575: MWA Observations
  19. LIGO/Virgo G194575: more details on transients from Pan-STARRS in the RA=1hr localisation region
  20. LIGO/Virgo G194575: Mini-MegaTORTORA observations
  21. GRB 151021A: MITSuME Okayama Ks-band upper-limit
  22. LIGO/Virgo G184098: TAROT network optical observations
  23. LIGO/Virgo G184098: iPTF Optical Transient Candidates
  24. LIGO/Virgo G184098: TAROT La Silla Observatory optical observations (TZAC)
  25. GRB 150915A: GROND detection of an optical counterpart candidate
  26. GRB 150907A: Swift-XRT afterglow detection
  27. GRB 150910A: MITSuME Ishigakijima Optical Observation after 1 day
  28. GRB 150910A: SAO RAS optical photometry
  29. Konus-Wind observation of GRB 150906B
  30. IPN Triangulation of GRB 150906B (short/intense)
  31. GRB 150907A: Swift-XRT observations
  32. ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
  33. Konus-Wind observation of GRB 150819B
  34. IPN Triangulation of GRB 150819B (short / very intense)
  35. GRB 150818A: Mondy optical observations
  36. GRB 150725A: MAXI/GSC detection
  37. Swift IGR J00291+5934: MASTER Optical flare detection
  38. Trigger 648422: Swift possible detection of a source in NGC4552
  39. Trigger 645944: Swift detection of H1745-203
  40. V404 Cyg: MASTER Swift, Integral alert observations
  41. GRB 150615A: Swift detection of a burst
  42. GRB150607A: Discovery Channel Telescope Optical Observations
  43. Konus-Wind observation of GRB 150607A
  44. Konus-Wind observation of GRB 150530A
  45. GRB 150530A: Fermi GBM observation
  46. GRB 150530A: Swift detection of a burst
  47. Konus-Wind observation of GRB 150523A
  48. GRB 150518A: MAXI-GSC further analysis
  49. Konus-Wind observation of GRB 150518A
  50. GRB 150518A: MAXI/GSC detection
  51. Swift Trigger 639636: a possible GRB
  52. GRB 150424A: Swift detection of a short burst
  53. GRB 150418A: Swift-XRT observations
  54. GRB 150403A: Swift-BAT refined analysis
  55. GRB 150403A: Swift/UVOT Detection
  56. GRB 150323C: Khureltogot optical observations
  57. GRB 150403A: Enhanced Swift-XRT position
  58. GRB 150403A: Swift detection of a burst with an optical counterpart
  59. GRB 150120B: GMG observation
  60. GRB 150323C: Mondy optical observations
  61. GRB 150323C: MASTER-net optical observation
  62. GRB 150318A: Skynet PROMPT-CTIO Observations
  63. GRB 150317A: Swift detection of a burst
  64. GRB 150313A: MAXI/GSC detection
  65. GRB 150305A: Swift XRT confirms weak INTEGRAL event as a new GRB
  66. GRB 150301C: XRT detection of a potential counterpart of BAT trigger 633105
  67. GRB 150302A: NOT afterglow candidate
  68. GRB 150302A: Swift detection of a burst
  69. GRB 150301A: GROND Observations
  70. GRB 150301A: Swift detection of a short burst or new SGR
  71. IPN Triangulation of GRB 150220A
  72. Trigger 631946: Swift detection of H1745-203
  73. Trigger 631747: Swift detection of 4U 0614+09
  74. GRB 150206B: Fermi GBM detection
  75. Swift Trigger 629693: probably not real
  76. GRB 150203A: P60 observations
  77. Swift Trigger 629206 is likely 1RXS J180408.9-342058
  78. GRB 150120B: Mondy optical observations
  79. Konus-Wind observation of GRB 150118B
  80. Trigger 626581: Swift detection of GRO J1008-57
  81. The Swift Detection of a Large Flare from the RS CVn Binary SZ Psc
  82. Swift detection of the variable star SZ Psc
  83. GRB 150110A: MAXI/GSC detection
  84. GRB 141220A: Swift-XRT refined Analysis
  85. GRB 141212A: MITSuME Okayama upper limits
  86. GRB 141207A: Swift-XRT afterglow candidate detection
  87. IPN Triangulation of GRB 141202A (short/hard)
  88. GRB 141121A: MITSuME Ishigakijima Optical Observation
  89. GRB 141121A: LCO-FTN observations
  90. GRB 141121A: MAXI/GSC detection
  91. IPN Triangulation of GRB 141118A
  92. GRB 141015A: TAROT La Silla observatory optical observations
  93. IPN Triangulation of GRB 141104A (long/very bright)
  94. GRB 141028A: SAO RAS Zeiss-1000 photometry
  95. GRB 141029B: Fermi GBM detection
  96. GRB 141022A: Swift detection of a burst
  97. Konus-Wind observation of GRB 141017A
  98. GRB 141017A: Zadko observatory - Gingin optical observations
  99. IPN Triangulation of GRB 141011A (short/hard)
  100. GRB 140930B: MASTER early possible OT detection

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov