NuSTAR hard X-ray data and Gemini 3D spectra reveal powerful AGN and outflow histories in two low-redshift Lyman-α\alpha blobs

We have shown that Lyman-$\alpha$ blobs (LABs) may still exist even at $z\sim0.3$, about 7 billion years later than most other LABs known (Schirmer et al. 2016). Their luminous Ly$\alpha$ and [OIII] emitters at $z\sim0.3$ offer new insights into the ionization mechanism. This paper focuses on the two X-ray brightest LABs at $z\sim0.3$, SDSS J0113$+$0106 (J0113) and SDSS J1155$-$0147 (J1155), comparable in size and luminosity to `B1', one of the best-studied LABs at $z \gtrsim$ 2. Our NuSTAR hard X-ray (3--30 keV) observations reveal powerful active galactic nuclei (AGN) with $L_{2-10{\;\rm keV}}=(0.5$--$3)\times10^{44}$ erg cm$^{-2}$ s$^{-1}$. J0113 also faded by a factor of $\sim 5$ between 2014 and 2016, emphasizing that variable AGN may cause apparent ionization deficits in LABs. Joint spectral analyses including Chandra data constrain column densities of $N_{\rm H}=5.1^{+3.1}_{-3.3}\times10^{23}$ cm$^{-2}$ (J0113) and $N_{\rm H}=6.0^{+1.4}_{-1.1}\times10^{22}$ cm$^{-2}$ (J1155). J0113 is likely buried in a torus with a narrow ionization cone, but ionizing radiation is also leaking in other directions as revealed by our Gemini/GMOS 3D spectroscopy. The latter shows a bipolar outflow over $10$ kpc, with a peculiar velocity profile that is best explained by AGN flickering. X-ray analysis of J1155 reveals a weakly absorbed AGN that may ionize over a wide solid angle, consistent with our 3D spectra. Extinction corrected [OIII] log-luminosities are high, $\sim43.6$. The velocity dispersions are low, $\sim100$--$150$ km s$^{-1}$, even at the AGN positions. We argue that this is a combination of high extinction hiding the turbulent gas, and previous outflows that have cleared the escape paths for their successors.Comment: 15 pages, 17 Figures, accepted for publication in Ap

NuSTAR hard X-ray data and Gemini 3D spectra reveal powerful AGN and outflow histories in two low-redshift Lyman-α blobs

We have shown that Lyα blobs (LABs) may still exist even at z ~ 0.3, about seven billion years later than most other LABs known (Shirmer et al.). Their luminous Lyα and [O III] emitters at z ~ 0.3 offer new insights into the ionization mechanism. This paper focuses on the two X-ray brightest LABs at z ~ 0.3, SDSS J0113+0106 (J0113) and SDSS J1155−0147 (J1155), comparable in size and luminosity to "B1," one of the best-studied LABs at z ≳ 2. Our NuSTAR hard X-ray (3–30 keV) observations reveal powerful active galactic nuclei (AGN) with L_(2-10 keV) = (0.5-3) x 10^(44) erg s^(−1). J0113 also faded by a factor of ~5 between 2014 and 2016, emphasizing that variable AGN may cause apparent ionization deficits in LABs. Joint spectral analyses including Chandra data constrain column densities of N_H = 5.1^(+3.1)_(-3.3) x 10^(23) cm^(−2) (J0113) and N_H = 6.0^(+1.4)_(-1.1) x 10^(22) cm^(−2) (J1155). J0113 is likely buried in a torus with a narrow ionization cone, but ionizing radiation is also leaking in other directions, as revealed by our Gemini/GMOS 3D spectroscopy. The latter shows a bipolar outflow over 10 kpc, with a peculiar velocity profile that is best explained by AGN flickering. X-ray analysis of J1155 reveals a weakly absorbed AGN that may ionize over a wide solid angle, consistent with our 3D spectra. Extinction-corrected [O III] log-luminosities are high, ~43.6. The velocity dispersions are low, ~100–150 km s^(−1), even at the AGN positions. We argue that this is a combination of high extinction hiding the turbulent gas and previous outflows that have cleared the escape paths for their successors

Before and After the Clean Water Act: How Science, Law, and Public Aspirations Drove Seven Decades of Progress in Maine Water Quality

In the 1950s, Maine established a water quality classification system creating the conceptual scaffolding of a tiered system of management. Passage of the federal Clean Water Act in 1972 drove dramatic advances in science, technology, and policy leading to systematic improvement for the next five decades. Today’s tiered classification system provides a range of management goals from natural to various allowable uses. The state assigns uses and standards for each classification, incorporating physical, chemical, and biological indicators. This system has brought steady improvement in water quality, ecological condition, and overall value for human use. Visible evidence of improvement and adoption of these management alternatives have inspired a re-imagining of how Maine’s waters can benefit clean water-based businesses, recreation, and amenity development