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"

7397 results found.

  1. XRF040812: possible afterglow second Chandra observation
  2. GRB 040812: Second epoch CXO Observations
  3. XRF040701: Second-Epoch Chandra Observations
  4. XRF 040701, optical observations
  5. GRB 040511, very fast decay?
  6. GRB 030324: Detection and Color of Host Galaxy
  7. GRB040511: Redshift identifcation
  8. GRB 040511: Optical limit
  9. GRB040511: Candidate optical/NIR afterglow
  10. GRB 040403: Optical Observations
  11. MASTER: RXTE GRB040308 optical observation
  12. RXTE GRB040229 optical observation: no candidate
  13. GRB 040228 Optical observations
  14. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  15. GRB040106: Second Epoch Optical Observations
  16. GRB 031220: Optical observations of Chandra X-ray sources
  17. GRB031220 : Optical Observation of Lulin Observatory
  18. GRB 031111: Optical observations
  19. GRB030913: Subaru Optical Observations
  20. GRB030913, candidate afterglow observations
  21. GRB 030913, optical candidate
  22. GRB 030824: Candidate Follow-Up
  23. XRF030824: optical observations
  24. XRF030824: Palomar observations
  25. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  26. RAPTOR observations of GRB030823
  27. GRB 021206 Optical Observations
  28. GRB030725: Optical observations
  29. XRF030723: Re-analysis of ROTSE-III early images
  30. GRB030725, optical transient observations
  31. XRF 030723: VLT spectra
  32. RXTE PCA Observations of SGR1806-20 Region
  33. GRB 021206, Radio afterglow candidate
  34. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  35. GRB 030519B: optical observations.
  36. GRB 030528: Optical observations at RIKEN
  37. GRB030324: Further Observations of the Candidate Optical Afterglow
  38. GRB 030429: IR photometry with IRSF/SIRIUS
  39. GRB030501: TAROT candidate afterglow present in archival images
  40. GRB 030501: TAROT possible candidate counterpart
  41. GRB 030429: confirmation of afterglow candidate
  42. GRB030429, possible optical counterpart
  43. GRB 030429: ROTSE-III observations
  44. GRB 030418: Optical afterglow
  45. GRB 030418: Finder for afterglow candidate
  46. GRB 030418: Optical afterglow candidate
  47. GRB030329, UBVRI polarimetry, R-polarization
  48. GRB030324: Candidate Optical Afterglow (Erratum)
  49. GRB030324: Candidate Optical Afterglow
  50. GRB030329, new UBVRcIc field photometry
  51. GRB 030329: Additional Mt. Laguna Optical Observations
  52. GRB 030329: optical observations
  53. GRB 030329: precise position from Kyoto images
  54. GRB 030329: Optical afterglow fading
  55. GRB 030329: Optical afterglow candidate
  56. GRB 030329: OT candidate
  57. GRB 030329: Optical afterglow candidate
  58. GRB 030328: Finding chart
  59. GRB 030328: Optical afterglow candidate
  60. GRB030324 optical observation
  61. GRB030131, BVRcIc field photometry
  62. GRB030324, optical observations
  63. GRB030324, optical observations
  64. GRB030323: V, R, I photometry
  65. VLT/FORS2 spectra of GRB 030323
  66. GRB030323, ROTSE-III detection of possible optical counterpart
  67. GRB030323, optical observations
  68. GRB030323, possible optical counterpart
  69. IPN upper limit to a GRB associated with SN2003L
  70. GRB 030227 optical afterglow
  71. GRB 030227: Confirmed Optical Afterglow (S1-A)
  72. GRB 030227: fading of candidate optical afterglow 'S1-A'
  73. GRB030227 - faint tentative OT candidate
  74. GRB 030226: Optical afterglow
  75. GRB030226: Candidate optical afterglow
  76. GRB 030131: marginal optical detection
  77. GRB030131: Candidate Optical Afterglow
  78. GRB 030131, optical observations
  79. GRB030131: Kiso optical limit for corrected position
  80. GRB030131: Optical limits for corrected position
  81. GRB 030131: afterglow candidate
  82. GRB 020819: afterglow candidate
  83. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  84. GRB030115 submm upper limit
  85. GRB 030115: Further IR observations with IRSF/SIRIUS
  86. GRB 030115: Radio detection of IR candidate
  87. GRB 030115: IR observations with IRSF/SIRIUS
  88. GRB030115: R-band counterpart of IR candidate
  89. GRB030115, afterglow candidate
  90. GRB 030115, no optical candidate
  91. GRB 030115, optical candidate
  92. GRB 021112: Evidence for Another Dark Optical Afterglow
  93. XRF 020903 : HST observations
  94. GRB021204: Kiso Observations
  95. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  96. HETE 2493: Optical observations
  97. HETE 2493: Optical candidate
  98. GRB 021112: Afterglow or Variable Star?
  99. GRB 021112, Radio Observations
  100. GRB 021112: Variable Source in R-band search

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