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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"

19569 results found.

  1. XRF030723: Palomar observations and proposed counterpart
  2. XRF030723, BVRcIc field photometry correction
  3. XRF030723, ROTSE-III Early Observations
  4. XRF030723, BVRcIc field photometry
  5. XRF 030723, optical observations
  6. XRF030723, optical observations
  7. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  8. SGR 1806-20, submm observations
  9. RXTE PCA Observations of SGR1806-20 Region
  10. GRB030329: Subaru Optical Spectroscopy
  11. GRB030329, optical observation in May
  12. IPN triangulation of GRB030626 (single large error box)
  13. IPN triangulation of GRB030626 (two large error boxes)
  14. HETE detection of burst from SGR1806-20
  15. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  16. IPN triangulation of GRB030606 (two alternate error boxes)
  17. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  18. GRB 030528: tentative NIR counterpart
  19. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  20. GRB030528, BVRI field photometry
  21. GRB030329, SPM optical observations
  22. GRB030528(=H2724): Revised SXC Localization
  23. GRB 030528 Bisei optical observation
  24. GRB030528 (H2724): A long GRB localized by HETE
  25. GRB 030528 (=H2724) Kyoto optical observation
  26. GRB030329, Optical observations
  27. GRB 030329 Optical Observations
  28. GRB 021004: HST observations
  29. GRB030324: Further Observations of the Candidate Optical Afterglow
  30. GRB030519B (=H2716): Peak Fluxes, Fluences, and Energy Spectrum
  31. HETE GRB030329, correction to Rc Observations in Loiano
  32. GRB 030329: Optical limit (contemporaneous imaging)
  33. IPN triangulation of GRB030509 (small errror box)
  34. IPN triangulation of GRB030509 - correction
  35. IPN triangulation of GRB030509 (single error box)
  36. GRB030429, refiend optical brightness
  37. GRB030418, BVRcIc field photometry
  38. GRB030429, BVRcIc field photometry
  39. GRB030329: RTT150 optical observations and upper limit for a host
  40. GRB 030429: redshift from VLT spectroscopy
  41. GRB030501: TAROT candidate afterglow present in archival images
  42. IPN triangulation of GRB030501B (annulus)
  43. GRB 030429: confirmation of afterglow candidate
  44. GRB 030329 Oprical observations in Rozhen observatory
  45. GRB030329, SPM optical observations
  46. GRB 030329, the review of the sky area in plate archive (1950-1998)
  47. GRB 030329: wide-field photograph by R. Tamura 1 hr after the burst
  48. GRB030329: optical polarization
  49. MASTER:optical observations GRB030418
  50. MASTER:optical observations probable GRB030414
  51. GRB030418: Upper limits from recent and historical observations.
  52. GRB030418: Kiso near infrared observations
  53. GRB030329: Optical Observations
  54. GRB 030329: SARA Optical Observations
  55. OT GRB 030329: early spectrum
  56. IPN triangulation of GRB030414 (small error box)
  57. GRB 030329 and SN 2003dh
  58. GRB030329, optical position
  59. GRB 030329 VLBA Observations
  60. GRB 030329, light curve flattens
  61. Kiso observation of the GRB030329 at April 6
  62. GRB 030329, color evolution
  63. GRB030328, UBVRcIc field photometry
  64. GRB 030329 Optical observations
  65. GRB 030329, color evolution
  66. GRB030329: Kiso B and R band observations
  67. SDSS 0.5m PT observations of GRB030329 (correction)
  68. SDSS 0.5m PT observations of GRB030329
  69. GRB030329: final R-band light curve by MASTER
  70. GRB030329, new UBVRcIc field photometry
  71. GRB 030329 , SPM optical observations
  72. GRB030329: Optical observations at Teramo
  73. GRB 030329: Radio observations at GMRT
  74. GRB 030329: Additional Mt. Laguna Optical Observations
  75. GRB 030329: Observations with ANDICAM
  76. GRB 030329: optical observations
  77. GRB 030324: Optical and NIR Observations
  78. GRB030329: R band light curve by MASTER
  79. GRB030329 - Light curve flattening
  80. GRB 030324, optical search
  81. GRB 030329, optical observations
  82. GRB030328: X-ray Fading and Spectrum Measured with Chandra
  83. GRB030329, BVRcIc field photometry
  84. GRB030329, SPM optical observations
  85. GRB 030329, optical photometry
  86. GRB030329 optical observations
  87. GRB 030329: Optical pre-Imaging
  88. GRB 030329: visual observations
  89. GRB 030329: Upper limit from 5.6 hours before trigger
  90. GRB030328: X-ray Afterglow Observed with Chandra
  91. GRB 030329, R-band observations
  92. GRB030329: Upper limits from recent and historical observations.
  93. GRB 030329: Optical Afterglow Observations
  94. GRB 030329: precise position from Kyoto images
  95. GRB 030328: Optical observations
  96. GRB 030328: optical observations
  97. GRB 030329: Optical afterglow fading
  98. GRB 030328: OT photometry
  99. GRB030328: optical photometry at the TNG
  100. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC

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