Zooniverse

Abstract:

We present a new catalogue of 5106 infrared bubbles created through visual classification via the online citizen science website 'The Milky Way Project'. Bubbles in the new catalogue have been independently measured by at least five individuals, producing consensus parameters for their position, radius, thickness, eccentricity and position angle. Citizen scientists - volunteers recruited online and taking part in this research - have independently rediscovered the locations of at least 86 percent of three widely used catalogues of bubbles and Hii regions whilst finding an order of magnitude more objects. 29 percent of the Milky Way Project catalogue bubbles lie on the rim of a larger bubble, or have smaller bubbles located within them, opening up the possibility of better statistical studies of triggered star formation. Also outlined is the creation of a 'heat map' of star formation activity in the Galactic plane. This online resource provides a crowd-sourced map of bubbles and arcs in the Milky Way, and will enable better statistical analysis of Galactic star formation sites. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

Abstract:

We report the detection of far-IR CO rotational emission from the prototypical Seyfert 2 galaxy NGC 1068. Using Herschel-PACS, we have detected 11 transitions in the J upper = 14-30 (E upper/kB = 580-2565K) range, all of which are consistent with arising from within the central 10″ (700pc). The detected transitions are modeled as arising from two different components: a moderate-excitation (ME) component close to the galaxy systemic velocity and a high-excitation (HE) component that is blueshifted by 80kms-1. We employ a large velocity gradient model and derive n H2 105.6cm-3, T kin 170K, and M H2 106.7 M ⊙ for the ME component and n H2 106.4cm-3, T kin 570K, and M H2 105.6 M ⊙ for the HE component, although for both components the uncertainties in the density and mass are ±(0.6-0.9)dex. Both components arise from denser and possibly warmer gas than traced by low-J CO transitions, and the ME component likely makes a significant contribution to the mass budget in the nuclear region. We compare the CO line profiles with those of other molecular tracers observed at higher spatial and spectral resolution and find that the ME transitions are consistent with these lines arising in the200pc diameter ring of material traced by H 2 1-0 S(1) observations. The blueshift of the HE lines may also be consistent with the bluest regions of this H2 ring, but a better kinematic match is found with a clump of infalling gas 40pc north of the active galactic nucleus (AGN). We consider potential heating mechanisms and conclude that X-ray- or shock heating of both components is viable, while far-UV heating is unlikely. We discuss the prospects of placing the HE component near the AGN and conclude that while the moderate thermal pressure precludes an association with the 1pc radius H2O maser disk, the HE component could potentially be located only a few parsecs more distant from the AGN and might then provide the N H 1025cm-2 column obscuring the nuclear hard X-rays. Finally, we also report sensitive upper limits extending up to J upper = 50, which place constraints on a previous model prediction for the CO emission from the X-ray obscuring torus. © 2012 The American Astronomical Society. All rights reserved.

Abstract:

The growth of supermassive black holes appears to be driven by galaxy mergers, violent merger-free processes and/or `secular' processes. In order to quantify the effects of secular evolution on black hole growth, we study a sample of active galactic nuclei (AGN) in galaxies with a calm formation history free of significant mergers, a population that heretofore has been difficult to locate. Here we present an initial sample of 13 AGN in massive (M_* >~ 1e10 M_sun) bulgeless galaxies -- which lack the classical bulges believed inevitably to result from mergers -- selected from the Sloan Digital Sky Survey using visual classifications from Galaxy Zoo. Parametric morphological fitting confirms the host galaxies lack classical bulges; any contributions from pseudobulges are very small (typically < 5%). We compute black hole masses for the two broad-line objects in the sample (4.2e6 and 1.2e7 M_sun) and place lower limits on black hole masses for the remaining sample (typically M_BH >~ 1e6 M_sun), showing that significant black hole growth must be possible in the absence of mergers or violent disk instabilities. The black hole masses are systematically higher than expected from established bulge-black hole relations. However, if the mean Eddington ratio of the systems with measured black hole masses (L/L_Edd = 0.065) is typical, 10 of 13 sources are consistent with the correlation between black hole mass and total stellar mass. That pure disk galaxies and their central black holes may be consistent with a relation derived from elliptical and bulge-dominated galaxies with very different formation histories implies the details of stellar galaxy evolution and dynamics may not be fundamental to the co-evolution of galaxies and black holes.

Abstract:

We present high-resolution maps of stars, dust, and molecular gas in a strongly lensed submillimeter galaxy (SMG) at z = 3.259. HATLAS J114637.9-001132 is selected from the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) as a strong lens candidate mainly based on its unusually high 500 μm flux density (300mJy). It is the only high-redshift Planck detection in the 130deg2 H-ATLAS Phase-I area. Keck Adaptive Optics images reveal a quadruply imaged galaxy in the K band while the Submillimeter Array and the Jansky Very Large Array show doubly imaged 880 μm and CO(1→0) sources, indicating differentiated distributions of the various components in the galaxy. In the source plane, the stars reside in three major kpc-scale clumps extended over 1.6kpc, the dust in a compact (∼1 kpc) region ∼3kpc north of the stars, and the cold molecular gas in an extended (∼7kpc) disk ∼5kpc northeast of the stars. The emissions from the stars, dust, and gas are magnified by ∼17, ∼8, and ∼7times, respectively, by four lensing galaxies at z ∼1. Intrinsically, the lensed galaxy is a warm (T dust ∼40-65 K), hyper-luminous (L IR ∼ 1.7 × 1013 L star formation rate (SFR) ∼2000 M yr-1), gas-rich (M gas/M baryon 70%), young (M stellar/SFR 20Myr), and short-lived (M gas/SFR 40Myr) starburst. With physical properties similar to unlensed z > 2 SMGs, HATLAS J114637.9-001132 offers a detailed view of a typical SMG through a powerful cosmic microscope. © 2012. The American Astronomical Society. All rights reserved..