Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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. LIGO/Virgo S190426c: GROWTH India follow-up
  2. LIGO/Virgo S190425z: SVOM/GWAC-F60A observations
  3. LIGO/Virgo S190425z: Liverpool Telescope imaging of ZTF19aasckkq
  4. LIGO/Virgo S190425z: No Optical Detection of the Swift/UVOT Transient in ASAS-SN observations hours before and after discovery
  5. LIGO/Virgo S190425z: Potential host galaxy of UVOT candidate counterpart found in BLISS
  6. LIGO/Virgo S190425z: Additional Candidates from the Zwicky Transient Facility
  7. LIGO/Virgo S190426c: DDOTI/OAN Optical Observations
  8. LIGO/Virgo S190425z: ASAS-SN observations
  9. If you have problems wrt GCN ( GRB, LIGO/Virgo, etc) and need to send email to the operator
  10. LIGO/Virgo S190425z: No Optical Detection of the Swift/UVOT Transient with Las Cumbres Observatory
  11. LIGO/Virgo S190425z: Pre-discovery NIR limits of the UVOT transient candidate from Gattini-IR
  12. LIGO/Virgo S190425z: Swift/UVOT and XRT pre-images at the position of the potential Swift/UVOT counterpart
  13. LIGO/Virgo S190425z: GROWTH-India observations of the Swift/UVOT transient
  14. Correction to GCN Circular 24301: LIGO/Virgo S190425z: Lulin observations of the Swift/UVOT transient
  15. LIGO/Virgo S190425z: ZTF photometry of the UVOT transient candidate hours before discovery
  16. LIGO/Virgo S190425z: Lulin observations of the Swift/UVOT transient
  17. LIGO/Virgo S190426c: RATIR Optical and NIR Observations of Galaxies
  18. LIGO/Virgo S190426c: J-GEM optical/NIR follow-up observations
  19. LIGO/Virgo S190426c: COATLI Optical Observations of Galaxies
  20. GRB 190419A: AstroSat CZTI detection
  21. LIGO/Virgo S190425z: Transient found in Swift/UVOT counterpart search
  22. LIGO/Virgo S190425z: Further confirmation for the classification of PS19qp/AT 2019ebq as a supernova
  23. Fermi GRB190427.19 Global MASTER-Net observations report
  24. GRB 190427A: Fermi GBM detection
  25. LIGO/Virgo S190426c: MMT Follow-Up Observations
  26. LIGO/Virgo S190426c: GOTO optical coverage - no notable counterparts
  27. GRB 190427A: Lick/Nickel telescope optical observations
  28. LIGO/Virgo S190426c: Lick/KAIT Follow-Up Observations
  29. GRB 190427A: MITSuME Akeno optical upper limits
  30. GRB 190427A: COATLI Optical Observations
  31. LIGO/Virgo S190426c: CNEOST Optical Observations
  32. LIGO/Virgo S190425z: CNEOST Optical Observations
  33. LIGO/Virgo S190426c: Infrared Wide-field Search with Palomar Gattini-IR
  34. LIGO/Virgo S190426c: Optical Wide-field Search with the Zwicky Transient Facility
  35. GRB 190427A: RATIR Optical and NIR Observations
  36. LIGO/Virgo S190426c: Nanshan/NEXT Observation of Galaxies
  37. LIGO/Virgo S190426c: Insight-HXMT/HE observation
  38. LIGO/Virgo S190426c: Updated localization to fix data format issue
  39. LIGO/Virgo S190426c: Hobby-Eberly Telescope VIRUS observations of target galaxies.
  40. LIGO/Virgo S190426c: Updated localization from LIGO and Virgo data
  41. LIGO/Virgo S190426c: CALET Observations
  42. LIGO/Virgo S190426c: Imaging confirmation and host spectroscopy of DG19vkgf
  43. LIGO/Virgo S190425z: Lulin Observations of Counterpart Search
  44. LIGO/Virgo S190426c: Swift-XRT sources
  45. GRB 190427A: BOOTES-1 and BOOTES-5/JGT early follow-up observations
  46. ANTARES follow-up of the GW candidate S190426c
  47. LIGO/Virgo S190425z: BOOTES-5/JGT observations of galaxies
  48. LIGO/Virgo S190425z - ePESSTO+ spectrum of candidate PS19qu
  49. LIGO/Virgo S190426c: Red and blue transients identified with DECam
  50. LIGO/Virgo S190425z: Lijiang 2.4-m Telescope Follow-up Observations
  51. LIGO/Virgo S190425z: Fermi-LAT search for a high-energy gamma-ray counterpart
  52. GRB 190427A: NOT optical observations
  53. GRB 190427A: Swift-XRT observations
  54. Swift GRB190427.19 Global MASTER-Net observations report
  55. LIGO/Virgo S190425z: Additional Pan-STARRS transients in the skymap
  56. GRB 190427A: Swift detection of a short burst
  57. LIGO/Virgo S190425z: ANU 2.3m early observations of ZTF19aarykkb
  58. LIGO/Virgo S190426c: MAXI/GSC Observations
  59. LIGO/Virgo S190426c: GROWTH India follow-up
  60. LIGO/Virgo S190426c: Public DECam Observations
  61. LIGO/Virgo S190425z: GRANDMA follow-up observations with Les Makes-T60, AZT-8 and Abastumani-T70
  62. LIGO/Virgo S190426c: Swift/BAT Counterpart Search
  63. LIGO/Virgo S190426c: STARE2 simultaneous L-band radio observations
  64. LIGO/Virgo S190425z: GRAWITA LBT spectroscopic observations
  65. LIGO/Virgo S190426c: Nemo is Unrelated
  66. LIGO/Virgo S190426c: a possible lensed NS-NS merger
  67. LIGO/Virgo S190426c: Tentative Red Transient Candidate from Las Cumbres Observatory
  68. LIGO/Virgo S190426c: Fermi GBM Observations
  69. LIGO/Virgo S190426c: SAO optical observation
  70. LIGO/Virgo S190426c: AGILE-GRID Observations
  71. LIGO-Virgo S190426c: AGILE MCAL observation
  72. LIGO/Virgo S190425z: Further MMT Follow-Up Observations
  73. LIGO/Virgo S190426c: Potential host galaxies from the GLADE catalog
  74. LIGO/Virgo S190426c: INTEGRAL prompt observation
  75. Baksan Neutrino Observatory Alert 190405.62: Global MASTER-Net:LIGO/Virgo S190425z: PanSTARR OT AT2019ebq/PS19qp
  76. LIGO/Virgo S190425z: Pierre Auger Observatory follow-up
  77. LIGO/Virgo S190425z: COATLI Observations of Galaxies
  78. LIGO/Virgo S190425z: RATIR Observations of Galaxies
  79. LIGO/Virgo S190426c: Identification of a GW compact binary merger candidate
  80. LIGO/Virgo S190426c Global MASTER-Net observations report
  81. LIGO/Virgo S190426c: HAWC follow-up
  82. LIGO/Virgo S190425z: YAHPT Optical Observation
  83. LIGO/Virgo S190425z: Keck NIR spectroscopy shows AT2019ebq is a supernova
  84. LIGO/Virgo S190425z: Nearby Galaxies in the Updated Localization Volume
  85. LIGO/Virgo S190426c: IceCube Neutrino Search
  86. LIGO/Virgo S190425z: J-GEM spectroscopic observations of AT2019ebq/PS19qp with Subaru/FOCAS
  87. LIGO/Virgo S190425z: GROND observations of AT2019ebq/PS19qp
  88. LIGO/Virgo S190425z: Updated localization from LIGO and Virgo data
  89. LIGO/Virgo S190425z: TAROT-GRANDMA observation report
  90. LIGO/Virgo S190425z: AMI-LA radio observations of two ZTF afterglow candidates.
  91. LIGO/Virgo S190425z: Las Cumbres Observatory Galaxy Targeted Counterpart Search
  92. LIGO/Virgo S190425z: GOTO observations
  93. LIGO/Virgo S190425z: ZTF pre-merger limits on PS1 candidates
  94. LIGO/Virgo S190425z: LWA1 observations
  95. LIGO/Virgo GW190425z: GTC spectroscopic classification of AT2019ebq/PS19qp
  96. LIGO/Virgo S190425z: DCT ZTF19aarykkb spectroscopy
  97. LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometry of ZTF19aarykkb and ZTF19aarzaod
  98. LIGO/Virgo S190425z: CALET Observations
  99. LIGO/Virgo S190425z - ePESSTO+ spectrum of PS19qp shows red featureless source at z=0.037
  100. LIGO/Virgo S190425z: KMTNet Observation

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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