Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. 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').

200 results found.

  1. LIGO/Virgo G298048: TOROS optical counterpart search (continuation)
  2. LIGO/Virgo G298048: TOROS optical counterpart search
  3. LIGO/Virgo G298048: optical observations of CHILESCOPE observatory
  4. LIGO/Virgo G298048: Pan-STARRS izy photometry monitoring of SSS17a/DLT17ck
  5. LIGO/Virgo G298048: VLA observation at 6 GHz
  6. LIGO/Virgo G298048: Continued VLA observations
  7. LIGO/Virgo G298048: Possible X-ray detection with Swift
  8. LIGO/VIRGO G298048: SALT optical spectra of the candidate optical/NIR counterpart of the gravitational wave G298048 in NGC4993.
  9. LIGO/Virgo G298048: Etelman Observatory observation of the potential LIGO EM counterpart SSS17a
  10. LIGO/Virgo G298048: GROND observations of candidate optical counterpart
  11. LIGO/Virgo G298048: Continued observation for DLT17ck
  12. LIGO/Virgo G298048: GMRT Follow-up of SSS17a
  13. LIGO/Virgo G298048: La Silla - QUEST archival non-detections of of LIGO EM counterpart SSS17a
  14. LIGO/VIRGO G298048: INAF VST-ESO PARANAL observations
  15. LIGO/Virgo G298048: KMTNet and other optical follow-up observations
  16. LIGO/Virgo G298048: further REM optical/NIR observations of candidate in NGC 4993
  17. LIGO/Virgo G298048: Subaru HSC z-band photometry confirms the fading nature of SSS17a
  18. LIGO/Virgo G298048: VLT linear polarimetry
  19. LIGO/Virgo G298048: GRAWITA VLT/X-shooter observations
  20. LIGO/Virgo G298048: NOT near-infrared observations of SSS17a
  21. LIGO/Virgo G298048: Further Pan-STARRS izy photometry confirms rapid fading of SSS17a/DLT17ck in i and z bands
  22. LIGO/Virgo G298048: Further VLA Observations
  23. LIGO/Virgo G298048: VLBA observations of the possible counterpart SSS17a in NGC 4993
  24. LIGO/Virgo G298048: MASTER photometry of the SSS17a in NGC 4993
  25. LIGO/Virgo G298048: HSC observations of the OT candidate of G298048
  26. LIGO/Virgo G298048: Possible features in the spectrum of GW counterpart SSS17a
  27. LIGO/Virgo G298048: GROND photometry of candidate optical counterpart reveals brightening in the NIR
  28. LIGO/Virgo G298048: Additional Swope Observations of SSS17a
  29. LIGO/VIRGO G298048: ePESSTO optical spectra of the candidate optical/NIR counterpart of the gravitational wave G298048 in NGC4993.
  30. LIGO/Virgo G298048: Rapid Evolution of Possible Counterpart
  31. LIGO/Virgo G298048: Observed fading of optical counterpart SSS17a
  32. LIGO/Virgo G298048: Continued observation for DLT17ck
  33. LIGO/VIRGO G298048: Expansion Velocity of SSS17a Consistent With Relativistic Merger Ejecta
  34. LIGO/Virgo G298048: optical spectral energy distribution of SSS17a
  35. LIGO/Virgo G298048: prior photometry from VISTA Hemisphere Survey
  36. LIGO/Virgo G298048: Archival 2MASS and Spitzer non-detections of the potential LIGO EM counterpart SSS17a
  37. LIGO/Virgo G298048: ATCA upper limits on radio emission from optical source SSS17a in NGC 4993
  38. LIGO/Virgo G298048: Continued Swift UV and X-ray Monitoring of SSS17a
  39. LIGO/Virgo G298048: Archival VLA observations
  40. LIGO/Virgo G298048: New MASTER observations of the OT in NGC 4993
  41. LIGO/Virgo G298048: Additional Gemini-South acknowledgements
  42. LIGO/Virgo G298048: UPDATE on IceCube neutrino candidates --- no coincidence with newest GW skymap
  43. LIGO/Virgo G298048: Correction to Swope photometry announced in LVC GCN 21529
  44. LIGO/Virgo G298048: Moderate dimming or no brightening of the optical counterpart candidate?
  45. LIGO/Virgo G298048: Brightening of Possible Counterpart
  46. LIGO/Virgo G298048: AGILE-GRID analysis of the potential counterpart field
  47. LIGO/Virgo G298048: Observation of the potential optical counterpart in NGC 4993
  48. LIGO/Virgo G298048: ASKAP search for fast radio bursts
  49. LIGO/Virgo G298048: Subaru HSC z-band photometry of the possible optical counterpart
  50. LIGO/Virgo G298048: SkyMapper uvgri photometry of the candidate in NGC 4933
  51. LIGO/Virgo G298048: ATCA detection of a radio source coincident with NGC 4993
  52. LIGO/Virgo G298048: TZAC TAROT Reunion (TRE) observations
  53. LIGO/Virgo G298048: Likelihood of SSS17a Being an Unrelated Extragalactic Transient in NGC 4993
  54. LIGO/Virgo G298048: REM optical/NIR observations
  55. LIGO/Virgo G298048, Fermi GBM trigger 524666471/170817.529: MAXI/GSC observations
  56. LIGO/Virgo G298048: HCT observations
  57. LIGO/Virgo G298048: Pan-STARRS detections and izy photometry of the possible optical/NIR counterpart in NGC4993
  58. LIGO/Virgo G298048: Gemini-South Near-Infrared Photometry of the Optical Transient Candidate
  59. LIGO/Virgo G298048: Magellan g-band Imaging of the Potential Optical Counterpart Associated with NGC 4993
  60. LIGO/VIRGO G298048: Swift UVOT detection and XRT upper limits
  61. LIGO/Virgo G298048: Subaru HSC follow-up observations
  62. LIGO/Virgo G298048: VLA Refined Analysis
  63. LIGO/VIRGO G298048: Magellan Optical Spectrum of the Potential Optical Counterpart Associated with NGC 4993
  64. LIGO/Virgo G298048: MASTER observations of the NGC 4993
  65. LIGO/Virgo G298048: VLA Detection
  66. LIGO/Virgo G298048: VISTA/VIRCAM detection of candidate counterpart
  67. LIGO/Virgo G298048: Galaxy-Targeted Optical Followup With Las Cumbres Observatory
  68. LIGO/Virgo G298048: Optical Candidate Shows No Evidence for Previous Activity in Archival SkyMapper Transient Survey Data
  69. LIGO/VIRGO G298048: The Potential Optical Counterpart in NGC 4993 Has Afterglow-Like Colors
  70. LIGO/Virgo G298048: DLT40 follow-up observation
  71. LIGO/Virgo G298048: Las Cumbres Observatory Detection of The Possible Optical Counterpart in NGC 4993
  72. LIGO/Virgo G298048: ATCA observations of candidate host galaxies
  73. LIGO/Virgo G298048: Inspection of archival HST data at the position of the potential optical counterpart
  74. LIGO/Virgo G298048: Nearby Galaxies in the Localization Volume using the updated sky map computed using LALInference
  75. LIGO/Virgo G298048 : Fermi-LAT search for a high-energy gamma-ray counterpart
  76. LIGO/Virgo G298048: Optical Candidate Shows No Evidence for Previous Activity in Archival ASAS-SN Data
  77. LIGO/Virgo G298048: REM optical/NIR observations of candidate in NGC 4993
  78. LIGO/Virgo G298048: DLT40 optical candidate
  79. LIGO/Virgo G298048: DECam optical candidate
  80. LIGO/Virgo G298048: Potential optical counterpart discovered by Swope telescope
  81. LIGO/Virgo G298048 - Update on Fermi/GBM GRB 170817A Analysis
  82. LIGO/Virgo G298048: Updated sky map from gravitational-wave data
  83. LIGO/Virgo G298048: AGILE GRID observations
  84. LIGO/Virgo G298048: AGILE MCAL observations
  85. LIGO/Virgo G298048: Swift/BAT data search
  86. LIGO/Virgo G298048 ANTARES search
  87. LIGO/Virgo G298048: Nearby Galaxies in the Localization Volume with Face-on Assumption
  88. LIGO/Virgo G298048: Nearby Galaxies in the Localization Volume
  89. LIGO/Virgo G298048: Insight-HXMT observations
  90. LIGO/Virgo G298048: Potential host galaxies from the GLADE catalog
  91. LIGO/Virgo G298048: IPN triangulation of Fermi/GBM trigger 524666471/170817529
  92. LIGO/Virgo G298048: Astrosat CZTI upper limits
  93. LIGO/Virgo G298048: Further analysis of a binary neutron star candidate with updated sky localization
  94. LIGO/Virgo G298048: COINCIDENT IceCube neutrino candidate with Fermi GBM trigger 524666471/170817529
  95. LIGO/Virgo G298048: correction to the luminosity distance reported in GCN 21509
  96. LIGO/Virgo G298048: Identification of a binary neutron star candidate coincident with Fermi GBM trigger 524666471/170817529
  97. LIGO/Virgo G298048: FOUND COINCIDENT IceCube neutrino observation
  98. LIGO/Virgo G298048: INTEGRAL detection of a prompt gamma-ray counterpart
  99. LIGO/Virgo G298048: Fermi GBM trigger 170817.529 and LIGO single IFO trigger
  100. LIGO/Virgo G298048: Fermi GBM trigger 524666471/170817529: LIGO/Virgo Identification of a possible gravitational-wave counterpart

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