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"

32703 results found.

  1. GRB 250106A: SVOM/VT 2nd optical deep observation
  2. GRB 250101A: J band upper limit by SYSU 80cm telescope
  3. GRB 250106A: NOT optical observations
  4. LIGO/Virgo/KAGRA S250104v: Updated Sky localization
  5. GRB 250103B: REM optical/NIR upper limits
  6. GRB 250101A: REM optical/NIR counterpart detection
  7. GRB 250106A: Swift-XRT observations
  8. GRB 250106A: SVOM/VT optical candidate
  9. GRB 250106A: Swift ToO observations
  10. GRB 241229A: SVOM/VT optical upperlimit
  11. GRB 250103B: LCO/1m optical afterglow candidate detection
  12. GRB 250103B: VLT/X-shooter spectroscopic redshift z = 1.416
  13. GRB 250103A: Swift-XRT observations
  14. GRB 250101A: 1.3m DFOT optical afterglow detection
  15. GRB 241229A: 1.3m DFOT upper limit
  16. GRB 241228B: 1.3m DFOT Optical observations
  17. GRB 241228A: 1.3m DFOT upper limit
  18. GRB 250103A: NOT spectroscopic redshift
  19. GRB 250103B：SVOM/VT optical counterpart
  20. LIGO/Virgo/KAGRA S250104v: Identification of a GW compact binary merger candidate
  21. GRB 250103A: Montarrenti Observatory optical detection
  22. GRB 250101A: further LCOGT optical afterglow observations
  23. GRB 250103A: Redshift 4.01 from OSIRIS+/GTC
  24. GRB 250103A: NOT optical observations
  25. GRB 250103A: TSHAO optical upper limit
  26. GRB 250103A: Fermi GBM Observation
  27. GRB 250103B: LCOGT Optical Upper Limit
  28. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  29. Swift GRB 250103B: Global MASTER-Net observations report
  30. GRB 250103A: SVOM/VT optical counterpart confirmation
  31. EP250101a: Liverpool Telescope optical upper limit
  32. GRB 250103A: Swift ToO observations
  33. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  34. GRB 250101a: Liverpool Telescope optical follow-up
  35. GRB 250103B: SVOM detection of a long burst
  36. GRB 250103A: Xinglong 2.16m Optical Candidate
  37. Fermi GRB 250102A: Global MASTER-Net observations report
  38. GRB 250101B: SVOM/GRM observation
  39. GRB 250103A: GOTO optical upper limit
  40. GRB 250103A: SVOM/C-GFT optical upper limit
  41. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  42. EP241231b: optical upper limit with the Liverpool Telescope
  43. EP250101a: Xinglong optical upper limit
  44. GRB 250101A: Swift-BAT refined analysis
  45. GRB 250101A: further SAO RAS optical observations
  46. GRB 250101A: LCO optical counterpart detection
  47. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  48. GRB 250101A: GMG spectroscopic redshift at z ~ 2.481
  49. GRB 250101A: Swift/UVOT Detection
  50. GRB 250101A: 1.6m Mephisto multi-band optical followup
  51. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  52. GRB 250101A: LCOGT optical afterglow detection
  53. GRB 250101A: OASDG optical observations
  54. Fermi GRB 250101B: Global MASTER-Net observations report
  55. GRB 250101A: SAO RAS observations of optical brightening
  56. GRB 250101A: AKO Optical Afterglow Detection
  57. GRB 250101A: SAO RAS optical observations
  58. LIGO/Virgo/KAGRA S250101k: Updated Sky localization and Source Classification
  59. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  60. GRB 250101A: SVOM/C-GFT early optical observations
  61. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  62. GRB 250101A: MASTER earlier OT observations with SOSS emission features
  63. GRB 250101A: Nanshan/HMT optical observations
  64. GRB 250101A : GIT optical detection
  65. GRB 250101A: GMG Optical Observation
  66. GRB 241217a/EP241217b: ATCA Radio Detection
  67. EP241217a: VLA Radio Detection

  68. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  69. GRB 241229B: Continued CrAO ZTSh observations
  70. LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
  71. LIGO/Virgo/KAGRA S241230ev: Updated Sky localization
  72. LIGO/Virgo/KAGRA S241230bd: Updated Sky localization
  73. GRB 241229A: EP-FXT X-ray afterglow confirmation
  74. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  75. GRB 241229B: SVOM/GRM observation
  76. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  77. EP241217A: J band upper limit by SYSU 80cm telescope
  78. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  79. GRB 241229B: SAO RAS optical upper limit
  80. GRB 241228B: SAO RAS optical observations
  81. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  82. GRB 241229A: SAO RAS optical observations
  83. GRB 241229B: SVOM/VT optical candidate
  84. GRB 241229A: Swift-XRT observations
  85. Konus-Wind detection of GRB 241228A
  86. GRB 241229A: EP-FXT afterglow candidates
  87. EP240702a: 7DT Optical upper limits
  88. GRB 240606B: 7DT Optical upper limits
  89. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  90. GRB 241229B: Swift-BAT refined analysis
  91. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  92. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  93. GRB241229B: UVOT upper limits
  94. GRB 241228B: D50 optical detection
  95. GRB 241228B: Fermi GBM Observation
  96. GRB 241229B: Fermi GBM Observation
  97. GRB 241229A: Swift ToO observations
  98. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  99. GRB 241228A: Mondy optical afterglow observations
  100. IceCube-241224A: No transient candidates from the Zwicky Transient Facility

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