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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. GRB 030429: Redshift of neighbor galaxy
  2. GRB030429, BVRcIc field photometry
  3. GRB030429: RTT150 optical obs., correction to GCN 2208
  4. GRB 030329: High-Resolution Spectroscopy of the Host
  5. GRB030429 (=H2695): A Long GRB Localized by the HETE WXM and SXC
  6. GRB030418 (=H2686): A Long, X-Ray-Rich GRB Localized by the HETE WXM
  7. XRF030416 (=U10897): An X-Ray Flash Localized by the HETE WXM
  8. GRB030429: RTT150 optical observations, a possible host galaxy
  9. IPN triangulation of GRB030506 (annulus)
  10. IPN triangulation of GRB030505B (large error box)
  11. IPN triangulation of GRB030505A (annulus)
  12. GRB030329: RTT150 optical observations and upper limit for a host
  13. GRB 030329: all-sky CCD images by K. Shiokawa immediately after the burst
  14. GRB030501, optical observation
  15. GRB030501 observation report
  16. GRB030501C triangulation (annulus)
  17. GRB030501 triangulation (correction to GCN 2194)
  18. GRB030329: RTT150 optical observations and upper limit for a host
  19. GRB 030429: Radio Observations
  20. GRB 030429: redshift from VLT spectroscopy
  21. GRB 030429: IR photometry with IRSF/SIRIUS
  22. GRB030501B triangulation (single error box)
  23. GRB 030329 Optical Observations
  24. GRB030328, optical observation
  25. GRB 030329, BVRI photometry
  26. GRB030429: Optical Observations
  27. GRB030501: TAROT candidate afterglow present in archival images
  28. GRB 030501: TAROT possible candidate counterpart
  29. IPN triangulation of GRB030501 (IBIS event; annulus)
  30. IPN triangulation of GRB030501B (annulus)
  31. GRB 030429: confirmation of afterglow candidate
  32. GRB030429, possible optical counterpart
  33. GRB030501 localized by INTEGRAL
  34. GRB030425: CrAO optical observation
  35. IPN triangulation of GRB030429 (annulus)
  36. IPN triangulation of GRB030428 (two large error boxes)
  37. GRB 030329 Oprical observations in Rozhen observatory
  38. GRB 030429: ROTSE-III observations
  39. GRB 030324: Radio Observations
  40. GRB030329 observed as a sudden ionospheric disturbance (SID)
  41. IPN triangulation of GRB030426 (annulus)
  42. SNeIa AS THE POSSIBLE PROGENITORS OF SHORT-DURATION GRBs.
  43. IPN triangulation of GRB030425 (single error box)
  44. GRB030329, SPM optical observations (Correction)
  45. GRB030329, SPM optical observations
  46. GRB 030329, the review of the sky area in plate archive (1950-1998)
  47. GRB 030329: Spectral Evolution of SN 2003dh
  48. Optical Observations of GRB 030418 with Magellan
  49. GRB 030329: optical spectropolarimetry at VLT
  50. IPN triangulation of GRB030422C (annulus)
  51. IPN triangulation of GRB030422B (annulus)
  52. GRB 030329: wide-field photograph by R. Tamura 1 hr after the burst
  53. GRB030329: optical polarization
  54. IPN triangulation of GRB030422 (two large error boxes)
  55. GRB 030329 3.5 and 6 cm radio observations at RTF-32 telescope
  56. GRB030329, optical observation
  57. IPN triangulation of GRB030421 (annulus)
  58. MASTER:optical observations GRB030418
  59. MASTER:optical observations probable GRB030414
  60. GRB030329: 444 AAVSO Measurements
  61. IPN triangulation of GRB030419 (annulus)
  62. MASTER:optical observations GRB030416
  63. ROTSE-III prompt optical detections of GRB 030418
  64. GRB030418: Upper limits from recent and historical observations.
  65. GRB030418: Kiso near infrared observations
  66. GRB 030418: Optical afterglow
  67. GRB 030418: Finder for afterglow candidate
  68. GRB 030418: Optical afterglow candidate
  69. GRB 030329 OT position
  70. GRB030329: Optical Observations
  71. OT GRB 030329: early UBVRcIc spectral evolution
  72. GRB030329, UBVRI polarimetry, R-polarization
  73. GRB 030329: SARA Optical Observations
  74. OT GRB 030329: early spectrum
  75. GRB030329: VR Photometry at TNG
  76. GRB030324: Candidate Optical Afterglow (Erratum)
  77. GRB030324: Candidate Optical Afterglow
  78. IPN triangulation of GRB030414 (small error box)
  79. GRB 030413: Optical Observations
  80. GRB 030329 Rc observations
  81. IPN triangulation of GRB030413 (small error box)
  82. IPN triangulation of GRB030410 (annulus)
  83. Superluminal motion in GRB 030329 (Correction)
  84. Superluminal motion in GRB 030329
  85. GRB 030329 and SN 2003dh
  86. GRB030329, optical position
  87. GRB 030329 VLBA Observations
  88. CORRECTION TO IPN TRIANGULATION OF GRB050403
  89. IPN triangulation of GRB030406 (small error box)
  90. IPN triangulation of GRB050403 (small error box)
  91. IPN triangulation of GRB030403 (annulus)
  92. GRB 030329: BVRI photometry at Asiago
  93. GRB 030329, light curve flattens
  94. GRB 030329: VLT V-band photometry
  95. If the SN/GRB connection confirmed
  96. GRB 030329: Supernova Confirmed
  97. GRB030329: RTT150 optical observations
  98. GRB030329: Near Infrared Observations at Gunma
  99. GRB030329: HET spectroscopic monitoring
  100. Kiso observation of the GRB030329 at April 6

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