Circumstellar Structure Around Evolved Stars in the Cygnus-X Spitzer Legacy Survey Region

Although the Cygnus-X region is primarily known as one of the richest massive star forming regions within 2 kpc, a large number of evolved objects also lie in, or at least along the line-of-sight to, the area observed by the Cygnus-X Spitzer Legacy Survey, including over 100 sources listed by Simbad as carbon stars, Wolf-Rayet stars, planetary nebulae, etc. Our Spitzer 24 micron images, made with the Multi-Band Imaging Photometer for Spitzer (MIPS), reveal previously undetected circumstellar emission from some of these objects. Emission at shorter wavelengths, observed using the Infrared Array Camera (IRAC), was also detected from some of the circumstellar structures, and a few were detected at longer wavelengths (MIPS 70 micron). Here, we present multi-wavelength Spizer images of the objects, including a bipolar nebula around a candidate carbon star BD +43 3710, a shell around the Wolf-Rayet candidate HBHA 4202-22, and a secondary shell around the luminous blue variable G79.29+0.46. In addition to the images, we combine near-infrared data from the 2 Micron All-Sky Survey (2MASS) with our Spitzer data to create spectral energy distributions for both the central objects and surrounding emission. Data from the Infrared Spectrograph (IRS) on Spitzer may also be discussed. We note that spiral structure has also been detected from a radio galaxy in our MIPS 24 micron data

Spectra of Massive Young Stars in the Cygnus-X Complex

2008sptz.prop50045FWe propose to use the IRS to obtain 5-40 um spectra of a sample of massive stars that are forming in the Cygnus-X region. Cygnus-X is the richest known region in IR-luminous and IR-quiet massive protostars within 2 kpc, and thus is a unique laboratory to study the poorly constrained early stages of massive star formation. The sample will be selected mainly from MSX sources and IR-quiet millimeter continuum sources, and will contain objects with a range of masses and at various stages of evolution. These data will enable us to determine how the properties of these massive stars change as they evolve towards the main sequence. We will also be able to examine the effects that these stars are having on their surroundings, including outflows into the nearby ISM and also in triggering further star formation

Exploring the Central Sub-parsec Region of the γ-Ray Bright Radio Galaxy 3C 84 with VLBA at 43 GHz in the Period of 2002-2008

Following the discovery of a new radio component right before the GeV γ-ray detection since 2008 August by the Fermi Gamma-ray Space Telescope, we present a detailed study of the kinematics and light curve on the central sub-parsec scale of 3C 84 using the archival Very Long Baseline Array 43 GHz data covering the period between 2002 January and 2008 November. We find that the new component "C3," previously reported by the observations with the Very Long Baseline Interferometer Exploration of Radio Astrometry, was already formed in 2003. The flux density of C3 increases moderately until 2008, and then it becomes brighter rapidly after 2008. The radio core, C1, also shows a similar trend. The apparent speed of C3 with reference to the core C1 shows moderate acceleration from 0.10c to 0.47c between 2003 November and 2008 November, but is still sub-relativistic. We further try to fit the observed broadband spectrum by the one-zone synchrotron self-Compton model using the measured apparent speed of C3. The fit can reproduce the observed γ-ray emission, but does not agree with the observed radio spectral index between 22 and 43 GHz