Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"
  1. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  2. GRB031225a triangulation (annulus)
  3. IPN triangulation of GRB031219 (large error box)
  4. GRB031220: Palomar Observations
  5. GRB 031220 : Kyoto Optical Observation
  6. GRB 031220: Subaru observation
  7. GRB 031220: Optical observation at Tokyo Tech
  8. GRB031220: ROTSE-IIIb Optical Limits
  9. GRB031220 : Optical Observation of Lulin Observatory
  10. GRB 031203 I-band monitoring
  11. IPN triangulation of GRB031214 (short/hard; very intense; small error box)
  12. GRB 2974 follow-up observations
  13. GRB031203, improved XMM position
  14. GRB 031203: Discovery of a dust echo
  15. GRB031214 triangulation (annulus), [repost of GCN2487, subject corrected]
  16. GRB030921 triangulation (annulus)
  17. GRB 031203: SMARTS optical monitoring
  18. GRB 021203: A Normal GRB viewed far off axis?
  19. XMM-Newton Observations of GRB031203: Preliminary Images
  20. GRB 031203: Variable Radio Source
  21. GRB 031203: Magellan spectrum of possible GRB host
  22. GRB 031203: Optical/IR Astrometry
  23. IPN/HETE localization of GRB031203B (=H2949; large error box)
  24. GRB031203 K prime photometry: correction to galaxy coordinates
  25. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  26. XMM-Newton Observation of GRB031203
  27. GRB 031203: Deep NIR NTT & VLT observations
  28. GRB031203: K' Photometry of the likely GRB host
  29. XMM-Newton Observation of GRB031203
  30. GRB 031203: Radio detection
  31. GRB 031203: Further reports on December 4 observations
  32. GRB 031203: IR NTTobservations do not confirm REM detection
  33. GRB031203 : Optical Observation of Lulin Observatory
  34. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  35. GRB 031203: Apparent Spectral Break
  36. GRB031203: Planned XMM-Newton observation II
  37. GRB 031203: IR REM Observations
  38. GRB031203: Optical Observations
  39. GRB 031203 XMM-Newton observation
  40. GRB 031203: Optical/IR SMARTS Observations
  41. GRB031203: Planned XMM-Newton observation
  42. IPN triangulation of GRB031127A and B (quasi-simultaneous; large error boxes)
  43. GRB 031203: further analysis of INTEGRAL data
  44. GRB 031203: A long GRB detected with INTEGRAL
  45. IPN triangulation of GRB031201 (large error box)
  46. IPN triangulation of GRB031130 (large error box)
  47. GRB031111A, prompt optical observations
  48. GRB 030329: Planned XMM-Newton Observation
  49. IPN triangulation of GRB031120 (two large error boxes)
  50. GRB 031111B (= H2925) : Kyoto Optical Observation
  51. IPN/HETE localization of GRB031109 (=H2917; large error box)
  52. IPN detection of activity from SGR1806-20
  53. GRB 031111, Radio observations
  54. IPN triangulation of GRB031114 (large error box)
  55. IPN triangulation of GRB031107 (two large error boxes)
  56. GRB 031111: Optical observations
  57. GRB 031111, optical observations
  58. SN 2003jd (SN/GRB?) -- X-ray Observations
  59. HETE Prompt GRB Spectral Analyses
  60. IPN triangulation of GRB031111 (=H2924): small error box
  61. XRF031109 (=H2919): A very long XRF localized by HETE
  62. IPN triangulation of GRB031108 (large error box)
  63. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  64. GRB030929/SN2003jd association unlikely based on IPN localiztion
  65. IPN triangulation of GRB031027 (small error box)
  66. IPN triangulation of GRB031026B (large error box)
  67. Lulin optical follow-up observations of GRB031026
  68. SN 2003jd (SN/GRB?), Radio Observations
  69. SN 2003jd (SN/GRB?) - possible association with GRB 030929
  70. GRB 031026: Further Ic Observations
  71. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  72. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  73. IPN triangulation of GRB031024 (single error box)
  74. GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
  75. GRB 031026: Ic Observations
  76. GRB031026 : KISO optical follow-up observation
  77. IPN triangulation of GRB031024 (annulus)
  78. IPN triangulation of GRB031020 (large error box)
  79. GRB030329: radio observations at RT-22 (CrAO)
  80. IPN triangulation of GRB031016 (two large error boxes)
  81. IBAS alert 1180 refers to a burst from SGR 1806-20
  82. HETE Prompt GRB Light Curves and Color-Color Diagrams
  83. IPN triangulation of GRB031014 (annulus)
  84. Ongoing Bursting Activity from SGR 1806-20 detected with IBAS
  85. XRF 030824: additional observations at CFHT
  86. SGR1806-20 bursts on 031008. Helicon detection and small error box.
  87. IPN triangulation of GRB031008 (annulus)
  88. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  89. IPN detection of continued activity from SGR1806-20
  90. IPN triangulation of GRB031007 (two large error boxes)
  91. XRF 030723: Subaru Optical Observations
  92. IPN triangulation of GRB031004B (annulus)
  93. IPN triangulation of GRB031004A (short/hard; annulus)
  94. IPN triangulation of GRB030929 (short/hard; annulus)
  95. A burst from SGR 1806-20 detected with IBAS
  96. XRF 030824: Early follow-up observation at Kiso observatory
  97. XRF 030824: observations at CFHT
  98. IPN triangulation of GRB030926 (short/hard; large error box)
  99. IPN triangulation of GRB030922B (large error box)
  100. XRF 030723: Detection of the likely host galaxy

Advanced

Download all Circulars as a .tar.gz archive:
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