Skip to main content
Circulars over Kafka event name backfill. 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. Non-detection of GRB050315 in ATCA Radio Observations
  2. GRB 050315: Swift XRT Position
  3. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  4. GRB 050315: Early Observations with Swift/UVOT
  5. Swift-BAT detection of GRB 050315
  6. GRB050223: No XMM-Newton OM detection of afterglow emission
  7. GRB 050306: Radio Observations
  8. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  9. GRB050309: CONCAM pre-trigger and trigger coincident optical
  10. GRB 050306: optical afterglow
  11. GRB 050126: Redshift determination
  12. Swift-BAT trigger 107873: No Swift XRT counterpart
  13. GRB 050306: Confirmation of X-ray afterglow
  14. GRB 050309, Early optical limits from RAPTOR
  15. GRB 050306: further TAROT optical data
  16. GRB050309: Early optical limit from P60
  17. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  18. GRB 050309 : Lulin R-band observation
  19. Swift 107873: P60 Optical Observations
  20. GRB 050306: CORRECTION to date of observation
  21. GRB 050306: R-band observations
  22. GRB 050306: No Swift UVOT Optical Counterpart Detected
  23. GRB 050306: REM optical-infrared observations
  24. GRB 050306: Possible X-ray Afterglow Position from the Swift
  25. Swift trigger 107518: optical observation
  26. GRB 050306: TAROT optical observations
  27. GRB 050306,optical observation
  28. GRB 050306: Swift-BAT detection of a long burst
  29. Ongoing activity of SGR 1806-20 after the giant flare
  30. GRB050215B: Late-Time Swift UVOT Observations
  31. GRB 050126: Confirmation of the NIR afterglow candidate
  32. PROMPT VRcIc Observations of GRB 050223
  33. XRF/GRB 050215B: Radio Observations
  34. XMM-Newton Images of GRB 050223
  35. GRB 050219b: candidate NIR afterglow
  36. IBAS GRB Alert #2321
  37. Confirmed XRF nature for GRB050215b
  38. GRB 050223: optical observations
  39. GRB050223 XMM-Newton observation
  40. INTEGRAL detection of GRB 050223
  41. GRB 050223 : Planned XMM-Newton observation
  42. GRB050223: No Swift UVOT Detection of Afterglow Emission
  43. GRB050223: ROTSE-III Optical Observations
  44. GRB 050223 Swift/BAT detection of a burst
  45. GRB 050223: Swift XRT Position
  46. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  47. GRB050219b: CORRECTION to time of UVOT observations
  48. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  49. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  50. GRB 050219b: CORRECTION to refined XRT position
  51. GRB 050219a: Optical observations from LCO
  52. GRB 050219b: Optical and near-IR observations from LCO
  53. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  54. GRB 050219b: Refined XRT position
  55. GRB 050219b: Swift-BAT detection of a burst
  56. GRB 050219b: CORRECTION: Swift XRT Position
  57. GRB 050219b: Swift XRT Position
  58. GRB 050219a, optical observations
  59. GRB 050219a: Refined XRT position
  60. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  61. GRB 050219: Swift-BAT detection of a burst
  62. GRB050215b: Swift UVOT Detection of Afterglow Emission
  63. GRB 050219: Prompt X-ray position
  64. GRB 050215B: Radio Observations
  65. GRB 050215b: XRT confirmation of IR afterglow candidate
  66. GRB050215b: P60 Optical Observations
  67. GRB 050215b: Swift XRT Source Variability
  68. GRB 050215B: candidate afterglow
  69. GRB 050215b : Lulin follow-up observation
  70. GRB 050215b, BOOTES-2 simultaneous optical observations
  71. GRB 050215B: UKIRT K-band imaging
  72. GRB 050215b: Swift XRT Observations
  73. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  74. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  75. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  76. GRB 050215b, BOOTES-1B optical limit
  77. GRB050215B: ROTSE-III optical observations
  78. GRB050215A: ROTSE-III Optical Observations
  79. GRB050209: TAROT optical observations
  80. GRB 050209(=U11568): Duration and spectrum
  81. short/hard GRB 050202, optical observations
  82. GRB050209: REM optical observations
  83. GRB 050209 I-band observation
  84. GRB 050209 Optical observations
  85. GRB050209: P60 Optical Observations
  86. GRB050209 (=U11568): A Long GRB Detected by HETE
  87. GRB 050209: Optical observation
  88. GRB 050128: Radio observations
  89. Further analysis of the short Swift-BAT GRB 050202
  90. GRB 050202: Second epoch radio observations
  91. GRB 050129: Optical observations
  92. GRB050202: Radio Observations
  93. GRB 050202: Optical observations with LCO40
  94. GRB 050202: Short burst detected by Swift-BAT
  95. GRB 050128 Optical observation with REM
  96. GRB 050129: a weak long GRB detected with INTEGRAL
  97. SGR1806-20: Swift-BAT detection of a large normal burst
  98. GRB050128: Faulkes Telescope South observations
  99. GRB 050124: Radio Observations
  100. GRB 050128: near-infrared observations with REM

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