Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

16167 results found.

  1. EP240816a: BOOTES-6/DPRT optical upper limit
  2. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  3. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  4. EP240816b: KAIT optical upper limit
  5. EP240816b: TRT optical upper limit
  6. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  7. GRB 240809A: ATA radio non-detection
  8. GRB 240809A: VLA detection
  9. GRB 240811A: Bassano Bresciano Observatory upper limit
  10. GRB 240811A: Swift/UVOT Upper Limits
  11. EP240801a: Assy-Turgen optical observations
  12. GRB 240811A: LCOGT Optical Upper Limit
  13. GRB 240811A: Upper limits with Mephisto
  14. GRB240809A: Liverpool Telescope optical follow-up observations
  15. GRB 240809A: REM detection of the optical afterglow
  16. GRB 240809A: Bassano Bresciano Observatory optical observations
  17. GRB 240809A: Conclusive redshift from VLT
  18. GRB 240809A: KAIT optical observations
  19. GRB 240809A: GIT afterglow observations
  20. GRB 240809A: Tentative redshift from NOT
  21. GRB 240809A: JinShan optical observations
  22. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  23. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  24. EP240807a: STEP/T80S optical limits
  25. EP-WXT trigger 01709018832: KAIT optical observations of the star flare
  26. EP240802a/GRB240802A: KAIT optical upper limit
  27. EP240806A: Liverpool Telescope optical follow-up observations
  28. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  29. EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
  30. GRB 240805B: GIT optical upper limit
  31. EP240806a: KAIT optical observations
  32. EP240804a (GRB 240804B): NOT optical observations
  33. EP240806a: LCOGT optical counterpart detection
  34. GRB 240805B Bassano Bresciano Observatory upper limit
  35. GRB 240805B: JinShan optical afterglow detection
  36. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  37. EP240806a: EP-FXT detection of the X-ray emission
  38. EP 240806A: LCO optical observations
  39. EP240806a: GSP optical counterpart detection
  40. GRB 240805B: Optical detection with 1.6m Mephisto
  41. EP240804a: BOOTES-6/DPRT optical detection
  42. GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
  43. GRB 240805B: Swift/UVOT Upper Limits
  44. GRB 240805A: Swift/UVOT Upper Limits
  45. GRB 240805B: BTA optical afterglow candidate
  46. GRB 240805B: LCOGT Optical Upper Limits
  47. GRB 240805B: JinShan optical upper limits
  48. EP240801a: BTA BVRI photometry
  49. EP240804a: GSP detects optical candidate counterpart
  50. EP240801a: Continued optical observations at ZTSh (CraO)
  51. EP240804a: LCOGT optical counterpart detection
  52. EP240804a: NOT optical counterpart detection
  53. GRB 240805A: Swift detection of a burst
  54. EP240802a: Montarrenti Observatory optical upper limit
  55. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  56. EP240802A: Bassano Bresciano Observatory upper limit
  57. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  58. EP240801a: further SAO RAS optical observations
  59. EP240801a: optical observations at CrAO and AbAO
  60. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  61. EP240801a: Leavitt Observatory optical observations
  62. EP240801a: GTC spectroscopy and absorption redshift
  63. EP240801a: SAO RAS optical observations
  64. EP240801a: JinShan optical observations
  65. EP240801a: NOT optical observations
  66. EP240801a: follow-up observation with LCOGT
  67. EP240801a: GSP follow-up observations of the candidate counterpart
  68. EP240801a: Kinder follow-up observations of the candidate counterpart
  69. EP240801a: KAIT optical counterpart observations
  70. EP240801a: GMG observation
  71. EP240801a: TRT optical counterpart detection
  72. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  73. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  74. GRB240730A: BOOTES-5/JGT early optical upper limit
  75. GRB 240730A: KAIT Optical Upper Limit
  76. GRB 240730A: Swift/UVOT Upper Limits
  77. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  78. GRB 240727A: observations of optical counterpart.
  79. GRB 240727A: Swift/UVOT detection
  80. GRB 240727A: Osservatorio Astronomico Nastro Verde upper limit
  81. GRB 240727A: NOT optical observation
  82. GRB 240727A: JinShan optical upper limits
  83. GRB 240727A Bassano Bresciano Observatory upper limit
  84. GRB240529A: VIRT optical transient detection
  85. GRB240727A: Skynet Optical Afterglow Observations
  86. GRB 240727A: TRT optical afterglow detection
  87. GRB 240727A: KAIT Optical Afterglow Candidate
  88. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  89. GRB 240713A: 2.2m CAHA optical limit
  90. GRB 240715A: Swift/UVOT observations of the XRT sources.
  91. GRB240713A: Swift/UVOT Upper LImits
  92. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  93. GRB 240713A: LAST optical upper limit
  94. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  95. GRB 240712A ATCA radio observations
  96. GRB240715A: GRANDMA Optical Upper Limits
  97. GRB 240712A: Swift/UVOT Upper Limits
  98. EP-WXT flaring star and the optical flaring activity during its decay phase
  99. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  100. The EP-WXT source triggered on July 14th is likely a flaring star

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