Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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. GRB030501B triangulation (single error box)
  2. GRB 030329 Optical Observations
  3. GRB030328, optical observation
  4. GRB 030329, BVRI photometry
  5. GRB030429: Optical Observations
  6. GRB030501: TAROT candidate afterglow present in archival images
  7. GRB 030501: TAROT possible candidate counterpart
  8. IPN triangulation of GRB030501 (IBIS event; annulus)
  9. IPN triangulation of GRB030501B (annulus)
  10. GRB 030429: confirmation of afterglow candidate
  11. GRB030429, possible optical counterpart
  12. GRB030501 localized by INTEGRAL
  13. GRB030425: CrAO optical observation
  14. IPN triangulation of GRB030429 (annulus)
  15. IPN triangulation of GRB030428 (two large error boxes)
  16. GRB 030329 Oprical observations in Rozhen observatory
  17. GRB 030429: ROTSE-III observations
  18. GRB 030324: Radio Observations
  19. GRB030329 observed as a sudden ionospheric disturbance (SID)
  20. IPN triangulation of GRB030426 (annulus)
  21. SNeIa AS THE POSSIBLE PROGENITORS OF SHORT-DURATION GRBs.
  22. IPN triangulation of GRB030425 (single error box)
  23. GRB030329, SPM optical observations (Correction)
  24. GRB030329, SPM optical observations
  25. GRB 030329, the review of the sky area in plate archive (1950-1998)
  26. GRB 030329: Spectral Evolution of SN 2003dh
  27. Optical Observations of GRB 030418 with Magellan
  28. GRB 030329: optical spectropolarimetry at VLT
  29. IPN triangulation of GRB030422C (annulus)
  30. IPN triangulation of GRB030422B (annulus)
  31. GRB 030329: wide-field photograph by R. Tamura 1 hr after the burst
  32. GRB030329: optical polarization
  33. IPN triangulation of GRB030422 (two large error boxes)
  34. GRB 030329 3.5 and 6 cm radio observations at RTF-32 telescope
  35. GRB030329, optical observation
  36. IPN triangulation of GRB030421 (annulus)
  37. MASTER:optical observations GRB030418
  38. MASTER:optical observations probable GRB030414
  39. GRB030329: 444 AAVSO Measurements
  40. IPN triangulation of GRB030419 (annulus)
  41. MASTER:optical observations GRB030416
  42. ROTSE-III prompt optical detections of GRB 030418
  43. GRB030418: Upper limits from recent and historical observations.
  44. GRB030418: Kiso near infrared observations
  45. GRB 030418: Optical afterglow
  46. GRB 030418: Finder for afterglow candidate
  47. GRB 030418: Optical afterglow candidate
  48. GRB 030329 OT position
  49. GRB030329: Optical Observations
  50. OT GRB 030329: early UBVRcIc spectral evolution
  51. GRB030329, UBVRI polarimetry, R-polarization
  52. GRB 030329: SARA Optical Observations
  53. OT GRB 030329: early spectrum
  54. GRB030329: VR Photometry at TNG
  55. GRB030324: Candidate Optical Afterglow (Erratum)
  56. GRB030324: Candidate Optical Afterglow
  57. IPN triangulation of GRB030414 (small error box)
  58. GRB 030413: Optical Observations
  59. GRB 030329 Rc observations
  60. IPN triangulation of GRB030413 (small error box)
  61. IPN triangulation of GRB030410 (annulus)
  62. Superluminal motion in GRB 030329 (Correction)
  63. Superluminal motion in GRB 030329
  64. GRB 030329 and SN 2003dh
  65. GRB030329, optical position
  66. GRB 030329 VLBA Observations
  67. CORRECTION TO IPN TRIANGULATION OF GRB050403
  68. IPN triangulation of GRB030406 (small error box)
  69. IPN triangulation of GRB050403 (small error box)
  70. IPN triangulation of GRB030403 (annulus)
  71. GRB 030329: BVRI photometry at Asiago
  72. GRB 030329, light curve flattens
  73. GRB 030329: VLT V-band photometry
  74. If the SN/GRB connection confirmed
  75. GRB 030329: Supernova Confirmed
  76. GRB030329: RTT150 optical observations
  77. GRB030329: Near Infrared Observations at Gunma
  78. GRB030329: HET spectroscopic monitoring
  79. Kiso observation of the GRB030329 at April 6
  80. GRB 030329, color evolution
  81. GRB030328, UBVRcIc field photometry
  82. GRB030329: Optical observcations
  83. GRB030329: BV photographic observations
  84. GRB 030329 Optical observations
  85. GRB 030329, color evolution
  86. GRB 030329: possible color change
  87. GRB030329: RTT150 optical observations
  88. GRB 030329: Supernova Spectrum Emerging
  89. GRB030329: Kiso B and R band observations
  90. GRB030329: RTT150 optical observation
  91. GRB030329: More AAVSO VR obs
  92. GRB030328: R upper limit after 6 hours by MASTER
  93. GRB 030329: BV photographic observations
  94. GRB 030329: SARA Optical Observations
  95. GRB 030329: SARA Optical Observations
  96. GRB030329, fading resumes
  97. GRB 030329, BVRI photometry
  98. GRB030329: Optical observations
  99. SDSS 0.5m PT observations of GRB030329 (correction)
  100. SDSS 0.5m PT observations of GRB030329

Advanced

Download all Circulars as a .tar.gz archive:
Looking for U.S. government information and services? Visit USA.gov