[C II] emission from galactic nuclei in the presence of X-rays

The luminosity of [C II] is used to probe the star formation rate in galaxies, but the correlation breaks down in some active galactic nuclei (AGNs). Models of the [C II] emission from galactic nuclei do not include the influence of X-rays on the carbon ionization balance, which may be a factor in reducing the [C II] luminosity. We calculate the [C II] luminosity in galactic nuclei under the influence of bright sources of X-rays. We solve the balance equation of the ionization states of carbon as a function of X-ray flux, electron, atomic hydrogen, and molecular hydrogen density. These are input to models of [CII] emission from the interstellar medium (ISM) in galactic nuclei. We also solve the distribution of the ionization states of oxygen and nitrogen in highly ionized regions. We find that the dense warm ionized medium (WIM) and dense photon dominated regions (PDRs) dominate the [C II] emission when no X-rays are present. The X-rays in galactic nuclei can affect strongly the C$^+$ abundance in the WIM converting some fraction to C$^{2+}$ and higher ionization states and thus reducing its [C II] luminosity. For an X-ray luminosity > 10$^{43}$ erg/s the [C II] luminosity can be suppressed by a factor of a few, and for very strong sources, >10$^{44}$ erg/s, such as found for many AGNs by an order of magnitude. Comparison of the model with extragalactic sources shows that the [C II] to far-infrared ratio declines for an X-ray luminosity >10$^{43}$ erg/s, in reasonable agreement with our model.Comment: 16 pages and 14 figures, accepted for publication in A&

Silicon chemistry in interstellar clouds

Interstellar SiO was discovered shortly after CO but it has been detected mainly in high density and high temperature regions associated with outflow sources. A new model of interstellar silicon chemistry that explains the lack of SiO detections in cold clouds is presented which contains an exponential temperature dependence for the SiO abundance. A key aspect of the model is the sensitivity of SiO production by neutral silicon reactions to density and temperature, which arises from the dependence of the rate coefficients on the population of the excited fine structure levels of the silicon atom. This effect was originally pointed out in the context of neutral reactions of carbon and oxygen by Graff, who noted that the leading term in neutral atom-molecule interactions involves the quadrupole moment of the atom. Similar to the case of carbon, the requirement that Si has a quadrupole moment requires population of the J = 1 level, which lies 111K above the J = 0 ground state and has a critical density n(cr) equal to or greater than 10(6)/cu cm. The SiO abundance then has a temperature dependence proportional to exp(-111/T) and a quadratic density dependence for n less than n(cr). As part of the explanation of the lack of SiO detections at low temperatures and densities, this model also emphasizes the small efficiencies of the production routes and the correspondingly long times needed to reach equilibrium. Measurements of the abundance of SiO, in conjunction with theory, can provide information on the physical properties of interstellar clouds such as the abundances of oxygen bearing molecules and the depletion of interstellar silicon

Governor William Langer Reply to Barratt O\u27Hara\u27s letter of March 10, 1934

Governor William Langer\u27s reply to Chicago radio personality (WCFL The Voice of Labor ) Barratt O\u27Hara\u27s letter about his radio address and the importance Langer brought to the show. Governor Langer also indicates solidarity with O\u27Hara and the thousands of petitioners regarding bond-holders\u27 request for constructive federal legislation.https://commons.und.edu/langer-papers/1057/thumbnail.jp

Letter from Governor Langer to Seth Richardson Regarding Bismarck Airport, 1934

February 1934 letter from North Dakota Governor William Langer to Seth Richardson, an attorney in Washington, D.C.. Langer notes that he has written two government officials regarding the establishment of an airport near Bismarck and Mandan. Governor Langer favors the development of a site at Ben Carl Ben Eielson Field, three miles west of the Bismarck post office on Highway 10. Langer closes the letter by asking Richardson to do whatever you can to help out in this matter.https://commons.und.edu/langer-papers/1068/thumbnail.jp

Letter to Sheriff Ross regarding Sam Bazant, December 15, 1919

Letter from Attorney General William Langer to Stutsman County Sheriff J.H. Ross in response to previous letter regarding Sam Bazant. Langer writes that he does not know where Bazant is and has not heard from him in a long time.https://commons.und.edu/langer-papers/1332/thumbnail.jp

Letter from Attorney General Langer to Cavalier County Sheriff regarding Enforcement of Liquor Laws, 1917

Letter dated July 5, 1917, from Attorney General William Langer to Cavalier County Sheriff Fred Thompson regarding the enforcement of liquor laws in Cavalier County. Langer acknowledges Thompson\u27s letter of July 3 and thanks him for his cooperation in the enforcement of the laws on the liquor question.https://commons.und.edu/langer-papers/1267/thumbnail.jp

Telegram from Senator Langer to M.A. Kirkeide Regarding Lack of Food and Clothing on the Fort Berthold Reservation, February 2, 1950

This document contains the text of a telegram dated February 2, 1950, from United States (US) Senator William Langer to Mountrail County Extension Agent M.A. Kirkeide. Langer acknowledges receipt of Kirkeide’s letter of January, 30, 1950 alerting Langer of a food and clothing shortage on the Fort Berthold Reservation. Langer\u27s telegram reads: “REURLET. MATTER HAVING IMMEDIATE ATTENTION. REGARDS. LANGER.” See also: Letter from M.A. Kirkeide to Senator Langer Regarding Lack of Food and Clothing on the Fort Berthold Reservation, January 30, 1950https://commons.und.edu/langer-papers/1731/thumbnail.jp

Letter from Senator Langer to Ben Reifel Regarding Trouble with Stray Horses, August 6, 1947

This letter dated August 6, 1947, from United States (US) Senator William Langer to Acting Superintendent of the Fort Berthold Agency Ben Reifel brings to Reifel’s attention Harris Grotte’s letter of August 5, 1947, regarding stray horses grazing on Grotte’s land. Grotte believes that someone is deliberately cutting his fences allowing stray tribal horses to get into his fields. Langer asks Reifel for further information in regard to this matter, and for any steps that can be taken to protect Grotte’s fields. Grotte\u27s letter, which Langer refers to as being enclosed, was not found with this letter in Langer\u27s papers. See also: Letter from Senator Langer to Harris Grotte Regarding Trouble with Stray Horses, August 5, 1947https://commons.und.edu/langer-papers/1721/thumbnail.jp

Telegram from Senator Langer to Patrick Gourneau Stating that Langer is Helping in Every Way Possible, April 25, 1956

This telegram dated April 25, 1956, from United States Senator William Langer to Patrick Gourneau of Turtle Mountain, responds to Gourneau\u27s telegram and says that Langer is helping in every way possible. A handwritten note at the top of the letter reads, Cross, Martin. See also: Telegram from Patrick Gourneau to Senator Langer Requesting that Langer Assist Martin Cross on His Present Mission in Washington, D.C., April 24, 1956https://commons.und.edu/langer-papers/1676/thumbnail.jp

Letter from Senator Langer to WF Gierke Regarding Fort Berthold Reservation, January 6, 1948

This letter dated January 6, 1948, from United States (US) Senator William Langer to WF Gierke Jr., acknowledges Gierke\u27s previous letter and states that he will continue addressing the issues related to the Three Affiliated Tribes of the Fort Berthold Reservation. There is a handwritten note at the top of the document that reads Indians. See also: Letter from Senator Langer to WF Gierke Regarding Fort Berthold Reservation, January 6, 1948https://commons.und.edu/langer-papers/1496/thumbnail.jp