Skip to main content
Announcing GCN Classic Migration Survey, End of Legacy Circulars Email. 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').
  1. SGR 1808-20 (=H2802): A Possible new SGR
  2. GRB 021206 Optical Observations
  3. IPN triangulation of GRB030808 (two large error boxes)
  4. IPN triangulation of GRB030806 (large burst; large error box)
  5. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  6. IPN/HETE summary of recent bursts from SGR1806-20
  7. XRF 030723: Detection of a rebrightening in the optical afterglow
  8. GRB030725: Optical observations
  9. XRF030723, BVRcIc field photometry update
  10. IPN triangulation of GRB030801 (large error box)
  11. GRB021206 optical counterpart upper limit
  12. IPN triangulation of GRB030731 (annulus)
  13. IBAS GRB Alerts 1011-1017 NOT CONFIRMED
  14. XRF030723: Re-analysis of ROTSE-III early images
  15. IPN triangulation of GRB030725 (=H2779; small error box)
  16. XRF030723 (=H2777): Second Epoch Magellan Observations
  17. GRB 030725: optical observations.
  18. GRB030725, optical transient observations
  19. IPN triangulation of GRB030726 (large error box)
  20. IPN triangulation of GRB030722 (large error box)
  21. IPN triangulation of GRB030721 (large error box)
  22. XRF030723 Radio Observations
  23. XRF 030723: confirmation of fading optical counterpart
  24. XRF030723(=H2777): Chandra Observations
  25. XRF 030723: VLT spectra
  26. Magellan Observations of XRF030723 (=H2777)
  27. GRB030723: Upper limits from historical observations
  28. GRB030725, possible optical transient
  29. XRF030723: Palomar observations and proposed counterpart
  30. GRB030725 (=H2779): A Bright GRB Localized by HETE
  31. XRF030723: optical observations
  32. XRF030723 (= H2777): Chandra Observations Scheduled
  33. XRF030723, BVRcIc field photometry correction
  34. XRF030723, ROTSE-III Early Observations
  35. XRF030723, BVRcIc field photometry
  36. XRF 030723, optical observations
  37. XRF030723, optical observations
  38. XRF 030723, optical observations
  39. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  40. GRB030723, optical observations
  41. Konus-Wind detection of the bursts from SGR1806-20 region
  42. IBAS GRB Alerts 969 970
  43. SGR 1806-20, submm observations
  44. H2768, H2770, and H2771: Three Bursts from SGR1806-20
  45. IPN triangulation of GRB030717 (annulus)
  46. RXTE PCA Observations of SGR1806-20 Region
  47. GRB030329: Subaru Optical Spectroscopy
  48. Triangulation of GRB030715 (single large error box)
  49. Triangulation of GRB030714 (single large error box)
  50. 030716 NOT a GRB
  51. IPN triangulation of GRB030714 (two large error boxes)
  52. IPN triangulation of GRB030715 (two large error boxes)
  53. GRB030329: RTT150 optical observations
  54. GRBlog: Compilation of all GCN Circ. data
  55. IPN detection of renewed activity from SGR1806-20
  56. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
  57. IPN triangulation of GRB030710 (annulus)
  58. IPN triangulation of GRB030709 (annulus)
  59. GRB030706 triangulation (single large error box)
  60. IPN triangulation of GRB030706 (annulus)
  61. IPN triangulation of GRB030629 (annulus)
  62. GRB030629 triangulation (Konus-Wind -- Helicon annulus)
  63. 030629 NOT a real GRB
  64. GRB030329, optical observation in May
  65. IPN triangulation of GRB030626 (single large error box)
  66. IPN triangulation of GRB030626 (two large error boxes)
  67. GRB030329: second XMM-Newton observation
  68. GRB030418: R optical observations
  69. HETE detection of burst from SGR1806-20
  70. GRB030329 -- RATAN-600 data in April-May
  71. Final IPN error ellipse for GRB021206 (the polarized GRB)
  72. GRB 021206, Radio afterglow candidate
  73. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  74. IPN triangulation of GRB030607 (annulus)
  75. IPN triangulation of GRB030606 (two alternate error boxes)
  76. GRB030329, SPM optical observations (Correction of GCN2075 R band)
  77. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  78. IPN triangulation of GRB030605B (annulus)
  79. GRB 030528: Optical Observations
  80. IPN triangulation of GRB030605 (annulus)
  81. GRB 030528: tentative NIR counterpart
  82. GRB 030528, radio observations
  83. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  84. GRB030329, further radio observations at GMRT
  85. GRB030528, BVRI field photometry
  86. IPN triangulation of GRB030601 (annulus)
  87. GRB030329, SPM optical observations
  88. GRB030528: Chandra TOO Planned
  89. GRB 030519B: optical observations.
  90. MASTER: optical observation GRB030601
  91. GRB030528(=H2724): Revised SXC Localization
  92. GRB 030329: optical observations
  93. GRB 030329/SN 2003dh: Jitter Episode
  94. GRB 030528, Teramo optical observation
  95. GRB 030528 Bisei optical observation
  96. GRB030528 (H2724): A long GRB localized by HETE
  97. GRB 030329: Correction to GCN 2254
  98. GRB 030329: Optical Observations
  99. GRB 030528: Optical observations at RIKEN
  100. GRB 030528 (=H2724) Kyoto optical observation

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