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

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