Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. 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"

28304 results found.

  1. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  2. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  3. EP241109a: confirmation of a stellar flare by BOOTES-7
  4. GRB 241108A: Swift-XRT observations
  5. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  6. EP241107a: KAIT optical observations
  7. GRB 241030A: TESS observations
  8. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  9. EP241107a: Kinder optical follow-up observations
  10. GRB 241025A: radio detection with the VLA
  11. EP241107a: AKO Optical Afterglow Follow-Up Observations
  12. EP241107a: GSP detects optical counterpart
  13. GRB 241105A: SVOM/GRM observation
  14. EP241107a: OHP/T193 photometric and spectroscopic observations
  15. GRB 241105a: PRIME near-infrared upper limits
  16. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  17. EP241107a: GIT optical observations
  18. EP241107a: SVOM/C-GFT optical observations
  19. EP241107a: AKO Optical Afterglow Detection
  20. GRB 241025A: LBT optical observations
  21. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  22. GRB 241105A: Swift/UVOT Detection
  23. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  24. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  25. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  26. GRB 241105A: Swift-XRT afterglow detection
  27. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  28. GRB 241104A: Swift-XRT observations
  29. GRB 240511A: LCO upper limits
  30. GRB 241104A: Fermi GBM Observation
  31. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  32. GRB 241104A: SVOM/VT optical candidate
  33. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  34. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  35. EP241104a: EP detection of GRB 241104A X-ray emission
  36. GRB 241010A: host galaxy redshift z = 0.977
  37. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  38. GRB 240821A: further radio observations with the VLA
  39. EP241103a: GIT optical upper limit
  40. EP241021a: OHP/T193 further optical observations
  41. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  42. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  43. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  44. EP241103a: Swift XRT detection and improved X-ray position
  45. EP241021a: continued SOAR observations
  46. EP241101a: Optical upper limits with Kinder observations
  47. EP241101a: OHP/T193 optical observations
  48. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  49. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  50. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  51. EP241103a: GSP optical upper limit
  52. EP241103A: LCO optical observations
  53. EP241103a: an X-ray transient detected by Einstein Probe
  54. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  55. S241102cy: Identification of a GW compact binary merger candidate
  56. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  57. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  58. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  59. GRB241030A: OHP/T193 optical observations
  60. GRB 241101A: FRAM-ORM optical limit
  61. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  62. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  63. EP241021a: Upper limit from Konus-Wind observations
  64. GRB 241101A: Swift-BAT refined analysis
  65. GRB 241030A: further SAO RAS optical observations
  66. GRB 241030A: Optical Observations via Virtual Telescope Project
  67. EP241021a: Liverpool Telescope optical follow-up observations
  68. GRB 241030B: Swift-XRT refined Analysis
  69. GRB 241026A: SAO RAS optical observations
  70. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  71. GRB 241101A: Swift detection of a burst
  72. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  73. EP241021a: OHP/T193 optical observations
  74. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  75. GRB 241030B: Montarrenti Observatory optical upper limit
  76. EP241026b: Liverpool Telescope optical follow-up
  77. GRB 241030A: SAO RAS optical observations
  78. GRB 241030A: Fermi GBM Observation
  79. EP241021a: AMI-LA radio detection
  80. GRB 241030B : GIT optical upper limits
  81. GRB 241030B: LCOGT Optical Upper Limits
  82. GRB 241030B: Swift-BAT refined analysis
  83. GRB 241030A: Swift-BAT refined analysis
  84. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  85. GRB 241030B: Swift/UVOT Detection
  86. GRB 241029A: LCO optical detection
  87. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  88. GRB 241030B : MITSuME Akeno optical upper limits
  89. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  90. GRB 241030B: SVOM/VT optical afterglow observations
  91. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  92. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  93. GRB241030B: Fermi GBM Observation
  94. GRB 241030B: BTA observations
  95. GRB 241029A: SVOM/VT optical afterglow observations
  96. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  97. GRB 241030B: Enhanced Swift-XRT position
  98. GRB241030B: GRANDMA/TAROT Upper Limit
  99. GRB 241030A: Swift-XRT refined Analysis
  100. GRB 241030B: SAO RAS optical observations

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