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"

26051 results found.

  1. GRB 070129: VLT observations
  2. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  3. GRB 070129: Swift detection of a burst
  4. GRB 070126: Swift/UVOT refined analysis
  5. GRB 070125: MITSuME Okayama optical observation
  6. GRB 070125: AAVSO optical observations
  7. GRB 070125: optical observations
  8. GRB 070126: VLT observations
  9. GRB070126: Swift-XRT possible detection of an afterglow
  10. GRB 070125: PROMPT detections
  11. GRB 070125: WSRT Radio Observations
  12. GRB 070125: UVOT Detection in Ultraviolet Filters
  13. GRB 070126, Swift-BAT refined analysis of a very faint burst
  14. GRB070124: Swift-XRT Observation
  15. Possible GRB 070126: Swift/UVOT Upper Limit
  16. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  17. GRB 070125: Xinglong TNT optical observations
  18. GRB 070125: Continued P60 Observations
  19. GRB 070125: pseudo-z~1.5 from spectral parameters of the prompt emission
  20. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  21. GRB 070125: Lick 3m Spectroscopy
  22. GRB070125: Swift-XRT Refined Analysis
  23. GRB 070125: SARA detection in R
  24. GRB 070125: P60 Optical Afterglow Candidate
  25. GRB 070126?: Swift detection of a possible burst
  26. IPN-BAT localization of GRB070125 (very long duration, intense)
  27. IPN localization of GRB070124 (short duration, hard spectrum)
  28. GRB 070110: optical break
  29. Swift-BAT trigger 257213 is a Galactic Center transient
  30. GRB 070110: Continued Detection and Request for Ground Followup
  31. GRB 050904: Second Epoch of HST/NICMOS Observations
  32. GRB 070110: Ep,i - Eiso correlation
  33. GRB 070110: VLT R-band photometry
  34. GRB 070110 declared a "Burst of Interest" by Swift team
  35. Further Retractions of previous Swift-BAT triggers
  36. Swift-BAT Trigger 255685 is not a GRB
  37. Trigger 255685: Swift detection of a possible burst
  38. GRB 070110: VLT absorption redshift
  39. GRB 070110: UVOT Observations of a Candidate Afterglow
  40. GRB070110: Swift XRT Team refined analysis
  41. GRB 070110, Swift-BAT refined analysis
  42. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  43. GRB 070110: Swift detection of a burst with a possible optical afterglow
  44. GRB070107: Swift/XRT refined analysis
  45. GRB 070107: Possible UVOT Afterglow
  46. GRB 070107, Swift-BAT refined analysis
  47. GRB 070107: Swift/XRT position
  48. GRB 070107: Swift detection of a burst
  49. VLA observation of GRB 061222B
  50. VLA detection of GRB 061222A
  51. GRB070103: APO SPIcam i' and z' limits
  52. GRB070103: KPNO 4m+FLAMINGOS J limit
  53. GRB 070103: Swift/UVOT Upper limits
  54. GRB070103: Swift XRT refined analysis
  55. GRB 070103, Swift-BAT refined analysis
  56. GRB 070103: NOT observations
  57. GRB 070103: TAROT Calern observatory optical observations
  58. GRB 070103: Swift detection of a burst
  59. Retractions of previous Swift-BAT triggers
  60. GRB061222a: optical observations
  61. Konus-Wind observation of GRB 061222A
  62. GRB 061210: Swift/XRT Astrometry Correction
  63. GRB 050826: MDM Redshift
  64. GRB 061222A: MITSuME Akeno optical upper limits
  65. GRB 061222A: Confirmation of Gemini Afterglow Candidate
  66. GRB 061222B: MITSuME Akeno optical upper limits
  67. GRB 061222A: Xinglong Optical Limit
  68. GRB 061222A: Gemini Afterglow Candidate
  69. GRB 061222B, Swift-BAT refined analysis
  70. GRB061222A Swift/UVOT: Upper Limits
  71. GRB 061222B: Swift/UVOT Upper limits
  72. GRB 061222B: Observation with the KANATA 1.5m telescope
  73. GRB061222B: Swift-XRT Refined Analysis
  74. GRB 061222A: Observation with the KANATA 1.5m telescope
  75. GRB 061222B: BOOTES-IR optical observations
  76. GRB 061222B: SARA upper limit
  77. GRB 061222A: Swift-XRT refined analysis
  78. GRB 061222A, Swift-BAT refined analysis
  79. GRB 061222B: REM NIR/optical observations
  80. GRB 061222b, SMARTS optical/IR afterglow observations
  81. GRB 061222B: TAROT La Silla observatory afterglow observation
  82. GRB 061222B: TAROT La Silla observatory optical observations
  83. GRB 061222b: Magellan redshift
  84. GRB 061222B: Swift detection of a burst
  85. GRB 061222b: optical afterglow
  86. GRB 061222A: Prompt ROTSE-III Optical Limits
  87. GRB 061222: Swift detection of a burst
  88. GRB 061217: Astrometry-Corrected XRT Position
  89. GRB 061201: Magellan redshift of nearby galaxy
  90. GRB 061217: Confirmation of host candidate
  91. GRB 061217: Object ib GCN 5948 is a star
  92. GRB 061217: Extended object in the revised XRT error circle
  93. GRB 061217, Candidate host galaxy
  94. GRB 061217 - Swift/XRT position correction
  95. GRB 061210: Possible Host Galaxy (S2-G2) Keck Spectrum
  96. GRB 061201: Magellan Redshift of nearby Abell cluster
  97. GRB 061218: TAROT La Silla observatory optical observations
  98. GRB 061217: TAROT Calern observatory optical observations
  99. GRB 061218, Swift-BAT refined analysis
  100. GRB061217: VLT NIR 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