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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"

43591 results found.

  1. GRB 990506, Optical Observations
  2. GRB 990506, optical observations
  3. GRB990506 observation plan
  4. Refined IPN error box for GRB990506
  5. GRB 990506: Limits on the possible optical transient
  6. GRB 990506, armchair astronomy
  7. GRB 990506, optical observations from +1 to +3 hours
  8. GRB 990506, optical observations
  9. GRB990506 Optical observations
  10. GRB990506 observation plan
  11. New IPN/RXTE error box for GRB990506
  12. IPN localization for GRB990506
  13. GRB 970228: Redshift and properties of the host galaxy
  14. GRB981220 VLBA observations
  15. GRB980425 Optical observations of exponential decline at late time
  16. GRB990323 PRECISE IPN POSITION
  17. GRB990321 IPN TRIANGULATION
  18. GRB 990316 Optical Observations
  19. GRB 990316, Radio observations
  20. GRB 990316, Optical observations
  21. GRB990316, Optical observations
  22. GRB 990316 optical observations
  23. GRB990316: simultaneous optical observation
  24. GRB990316 - Optical null results
  25. ASM/IPN error box for GRB 990308 (BATSE #7457)
  26. GRB990308 not a new SGR
  27. GRB 990308a and GRB 990308b
  28. GRB990308 (Trig. 7457), optical observations
  29. GRB990308, Possible new SGR~0209+70
  30. GRB981220, IPN localization
  31. GRB 981220, radio observations
  32. GRB 990123, Field Photometry
  33. GRB 990217, radio observations
  34. BATSE Resumes Normal Operations
  35. BATSE Flight Anomaly
  36. GRB990217: BeppoSAX/GRBM data
  37. Optical Observations of GRB990217
  38. GRB990123: Caltech STIS Photometry and Images
  39. GRB990123 observations
  40. GRB990217, WFC position
  41. GRB990123, Optical Observation
  42. GRB 990123: Discovery of the Probable Host Galaxy
  43. GRB 990123: Reduced HST Images
  44. For Immediate Posting to GCN - HST Data GRB 990123 Available
  45. GRB19990123 observations
  46. GRB 990123: Updated Keck Spectroscopy Results
  47. GRB981220, field photometry
  48. GRB 990123 NOT Spectrum Update
  49. GRB990123, Optical observation
  50. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  51. GRB 990123: Publicly available reduced HST images
  52. GRB990123, Upcoming HST Service Observations
  53. GRB990123, 15-GHz limits
  54. GRB 990123: New Constraints on Possible Foreground Galaxies
  55. GRB990123 Optical Observations
  56. GRB990123, Probability of gravitational lensing
  57. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  58. GRB 990123: Continued Radio Observations
  59. GRB990123, Preliminary Lens Search Results
  60. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  61. On the Lensing Interpretation of GRB 990123
  62. Search for Potential Images of GRB 990123
  63. Search for Potential Images of GRB 990123
  64. GRB990123, Optical BVRI Observations
  65. GRB 990123: near-infrared observations.
  66. GRB990123, OSSE observations
  67. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  68. GRB990123: NIR Observation
  69. GRB990123, ASCA X-ray observation of afterglow
  70. GRB 990123 Optical Follow-Up
  71. GRB 990123: BATSE Observations
  72. GRB 990123 Keck Spectrum update
  73. GRB990123 IPN annulus
  74. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  75. GRB990123 Optical Observations
  76. GRB 990123 Spectroscopic Redshifts
  77. GRB 990123: New Optical Observations, Decay Measure
  78. GRB 990123 Optical Follow-Up
  79. GRB 990123: Possible Gravitationally Lensed Burst?
  80. GRB 990123 optical observations
  81. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  82. GRB 990123 radio observations
  83. GRB 990123, new radio source
  84. GRB990123 optical observations
  85. GRB990123, Optical observation
  86. GRB 990123: Optical Decay Slope
  87. GRB 990123 r-band photometry
  88. GRB 990123 Optical Follow-up
  89. GRB990123, early optical counterpart detection
  90. GRB990123 Optical Observation
  91. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  92. GRB990123, refined SAX-WFC position
  93. GRB 990123: Bright New Source, Possible Optical Transient
  94. GRB 990123, Radio observations
  95. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  96. SN 1999E & GRB 980919
  97. Possible identification of SN1999E with GRB980910
  98. Optical Observations of GRB 981220
  99. GRB 981226: radio variable
  100. GRB981220

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